Male Genitourinary System

Clinical Features

Clinical classification of acute and chronic prostatitis

• Acute bacterial prostatitis

• Chronic bacterial prostatitis

• Chronic abacterial prostatitis

• Prostate is swollen and tender on palpation

• Often refractory to antibiotic therapy because the prostate is a “safe haven” for bacteria

• Patients may present with recurrent urinary tract infections

• Cultured organisms are the same as those seen in urinary tract infections (i.e., Escherichia coli , other gram-negative rods, and Enterococcus and Staphylococcus species)

• Same as acute prostatitis, but symptoms are of longer duration

• Most common form of clinical prostatitis

• Presents similar to acute and chronic bacterial prostatitis

• By definition, no organisms are cultured (idiopathic); however, infection by Chlamydia, Ureaplasma , or Mycoplasma species has been suggested

• Nonspecific (idiopathic) granulomatous type

• Patients are between 20 and 70 years of age (mean age, 60 years)

• Patients present with obstructive symptoms, dysuria, fever, and chills; may have a history of urinary tract infection

• Prostate on palpitation can be firm and indurated (may clinically mimic carcinoma)

• After bacillus Calmette-Guérin (BCG) therapy: history of intracystic BCG therapy for transitional cell carcinoma (TCC) may be remote ( Figure 11.1B )

  

• Post-transurethral or postbiopsy granulomatous type: history of procedure up to 5 years ago

• Infectious granulomatous type: history of infection by any one of the following

  • Bacteria (tuberculosis, syphilis, or brucella)

  • Fungi (cryptococcosis, blastomycosis, or coccidioidomycosis)

  • Viruses (herpes)

  • Parasites (schistosomiasis, echinococcosis)

• Primarily affects men older than 50 years

• Symptoms include fever, frequency, dysuria, and hematuria

• Urine culture is often positive for E. coli

Gross Pathology

• Acute and chronic bacterial and chronic abacterial prostatitis

  • Prostatic enlargement; may be soft and swollen

• Granulomatous prostatitis

  • Enlarged with firm, nodular parenchyma

  • Areas of infarction and necrosis with infectious granulomas are often seen

Histopathology

• Acute and chronic bacterial prostatitis

  • Prominent neutrophilic infiltrate with abscess formation

  • Neutrophils and necrotic debris may fill prostatic ducts and acini

  • Reactive glandular epithelium showing mild cytologic atypia; nuclei with prominent nucleoli may be seen ( Figure 11.1A )

  • Glands may appear atrophic and have a pseudocribriform architecture owing to little glands budding off within lumen

  • Stroma is edematous and hyperemic

• Chronic abacterial prostatitis

  • Presence of neutrophils and lymphocytes in prostatic ducts and epithelium

  • Reactive glandular epithelium showing mild cytologic atypia; nuclei with prominent nucleoli may be seen

  • May be associated with glandular atrophy

• Granulomatous prostatitis

• Nonspecific (idiopathic) granulomatous type

  • Admixture of histiocytes, plasma cells, eosinophils, neutrophils, lymphocytes, and giant cells

  • Cells arranged in sheets around ruptured ducts and acini

• Post-BCG therapy

  • Mostly histiocytes and giant cells associated with ducts or acini ( Figure 11.1B )

• Posttransurethral or postbiopsy granulomatous type

  • Central zone of fibrinoid necrosis surrounded by palisading histiocytes and some multinucleated giant cells ( Figure 11.1C )

  • Minimal chronic inflammatory infiltrate

  • Eosinophilic infiltrate typically presents after recent prostate surgery (1 month after resection)

• Infectious granulomatous type

  • Granulomatous inflammation, with or without necrosis

  • Eosinophils often present with parasitic infection

• Malakoplakia

  • Hansemann cells: histiocytes with clear or eosinophilic cytoplasm arranged in sheets with surrounding mixed chronic inflammatory infiltrate

  • Michaelis-Gutmann bodies: round, target-shaped structures found intracellularly and extracellularly

Special Stains and Immunohistochemistry

• Granulomatous prostatitis

  • Nonspecific granulomatous type

    • Stains positively for histiocytic markers, negative for epithelial markers

  • Infectious granulomatous type

    • May identify causative organism with special stains (Gomori methenamine silver, periodic acid-Schiff [PAS], acid-fast bacillus stains)

  • Malakoplakia

    • Von Kossa calcium, iron, and PAS highlight Michaelis-Gutmann bodies

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

Clinical Features

• Patients may be asymptomatic or present with urinary retention and hematuria

• Typically occurs in a background of nodular hyperplasia

Gross Pathology

• In general, the greater the degree of nodular hyperplasia, the greater the likelihood of infarction

• Central pale-yellow zone surrounded by hyperemic tissue

Histopathology

• Acute infarction

  • Central coagulative necrosis with surrounding hemorrhage ( Figure 11.2 )

    

  • Adjacent glands show reactive and metaplastic changes; typically squamous metaplasia

  • Reactive glandular epithelium is characterized by cells with enlarged nuclei, prominent nucleoli, and mitotic figures

• Remote infarction

  • Central fibrous scar with hemosiderin admixed with small glands often showing squamous metaplasia

Special Stains and Immunohistochemistry

• Noncontributory

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

Clinical Features

• Common in males after 60 years of age

• Patients may have symptoms of urinary obstruction (inability to initiate or terminate urinary flow) or may be asymptomatic

Gross Pathology

Histopathology

Special Stains and Immunohistochemistry

• HMWCK: highlights basal cell layer in benign (nodular) prostatic hyperplasia, BCH, clear cell cribriform hyperplasia, and sclerosing adenosis

• (MSA) and S-100 protein positive in some basal and spindle cells in sclerosing adenosis (indicates myoepithelial differentiation)

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

Clinical Features

Gross Pathology

• Nonspecific

Histopathology

Special Stains and Immunohistochemistry

• HMWCK positive in urothelial and transitional cells and squamous metaplasia

• Alcian blue and mucicarmine positive for intracytoplasmic acid mucin in mucinous metaplasia

• PAS positive for neutral mucin in mucinous metaplasia (diastase resistant)

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

Clinical Features

• High-grade prostatic intraepithelial neoplasia (PIN) is considered to be a premalignant condition based on morphologic, epidemiologic, and genetic features

• In autopsy series, high-grade PIN precedes carcinoma by 10 years and is common in the fourth decade of life

• Currently, high-grade PIN is associated with adenocarcinoma on rebiopsy in 25% of patients, significantly less than the 50% association reported in patients biopsied in the late 1980s (see “Pearls”)

• Presence of high-grade PIN mandates rebiopsy; however, it is unclear that chasing PIN has any benefit (i.e., it simply results in the detection of clinically insignificant prostate cancers)

• Clinical significance of low-grade PIN is unclear; should not be diagnosed

Gross Pathology

• Nonspecific

Histopathology

• Low-grade PIN

  • Morphologic features not rigorously defined and subjective; should not be diagnosed

• High-grade PIN

  • Four patterns include tufted, cribriform, micropapillary, or flat

  • Cells have enlarged nuclei with prominent nucleoli ( Figure 11.4 )

    

  • Basal cells are present but may be attenuated

Special Stains and Immunohistochemistry

• HMWCK and p63: basal cell layer is immunopositive but may be thin and attenuated

• α-Methylacyl coenzyme A racemase (AMACR): high-grade PIN may be positive but more apical and granular and less intense than carcinoma

Other Techniques for Diagnosis

• Morphometric studies: high-grade PIN and adenocarcinoma have similar cytologic features (i.e., nuclear area, nuclear perimeter size, nuclear shape, amount and distribution of chromatin, and nucleolar changes)

Differential Diagnosis

Clinical Features

• Most common cause of cancer in men; second most common cause of cancer death after lung cancer

• One in five American men will be diagnosed with prostate cancer

• Occurs predominantly in men older than 50 years

• More prevalent in black men and rare in Asians

• Familial predisposition exists

• Because of the typical location of prostatic carcinoma (posterior aspects of the peripheral zone), urinary symptoms occur late; asymptomatic tumors are often detected by digital rectal examination or after routine examination that detects elevated PSA

• Advanced disease may cause obstructive symptoms (difficulty initiating or terminating urination, frequency, or dysuria)

• Metastases to bone may cause osteoblastic or osteolytic lesions; however, in men, the demonstration of osteoblastic bone metastases is virtually diagnostic of metastatic prostate carcinoma

• Back pain is a common finding in patients with metastatic disease

• Screening methods

  • Digital rectal examination: cancer focus may be nonpalpable or indurated

  • PSA levels greater than 4 ng/mL (some advocate 2 ng/mL) prompt biopsy

  • Random bilateral biopsies now standard of care in select patients with nonpalpable disease

  • Transrectal ultrasound with biopsy

• Elevated PSA is not sensitive or specific for prostatic cancer; other benign conditions, including inflammatory processes or nodular hyperplasia, may cause slight PSA elevation

• PSA levels do not distinguish between significant and insignificant cancers; identification of such biomarkers (e.g., EPCA-2, PCAs, TMPRSS2-ERG) is an active area of research

• Elevated PSA in patients after treatment for prostatic carcinoma is a useful indicator of recurrent or progressive disease

Gross Pathology

Histopathology ( Figure 11.5 )

Acinar (Conventional) Adenocarcinoma

• Constitutes more than 95% of prostate cancer

• Low-power magnification

  • Majority show haphazard proliferation of fairly uniform acini infiltrating between benign elements

  • Occasionally the acini are intermediate-sized (“microcystic”) or dilated and filled with complex, branching epithelial cells (“pseudohyperplastic”)

  • High-grade tumors tend to grow in cords, nests, or sheets;

  • See Gleason grading system ( Figure 11.6 )

    

• High-power magnification

  • Acini are lined by a single layer of epithelial cells; basal cell layer is absent

  • Epithelial cells are cuboidal or columnar and have abundant amphophilic cytoplasm and enlarged, variably pleomorphic nuclei with one or more prominent macronucleoli

  • Mitotic figures are a helpful feature of malignancy but are uncommon, especially in low-grade tumors

  • Features pathognomonic for carcinoma include glomeruloid structures, mucinous fibroplasias (collagenous micronodules), circumferential perineural invasion, and extraprostatic extension

  • Blue-tinged mucinous material, amorphous eosinophilic material, and crystalloid within lumina of neoplastic glands (less common in benign glands) may be seen

• Corpora amylacea is rare (much more common in benign conditions)

Special Stains and Immunohistochemistry

• AMACR

  • Sensitive and specific marker for conventional (acinar) prostate cancer; positive in 82% to 100% of cases

  • Less sensitive in low-grade and hormone-treated conventional prostate cancer and prostate cancer variants, such as foamy gland, pseudohyperplastic, atrophic-type, and ductal-type prostate cancers

  • Positive but less intense, noncircumferential or only focal in high-grade PIN, atypical adenomatous hyperplasia, atrophy, nephrogenic adenoma, and benign glands adjacent to cancer

  • AMACR is less useful in evaluating metastases because many tumors in other organs are immunopositive

• HMWCK and p63

  • Stains basal cell cytoplasm (HMWCK) and nuclei (p63); therefore, negative in adenocarcinoma because basal cells are absent

• PSA and prostatic acid phosphatase (PAP) positive for tumor cells of mucinous, signet ring cell, and ductal-type variants of adenocarcinoma; also positive in epithelial component of sarcomatoid carcinoma

• Carcinoembryonic antigen (CEA) positive in some ductal-type variants of carcinoma

• Vimentin: spindle cell component of sarcomatoid carcinoma positive

• Desmin, smooth muscle actin (SMA), and S-100 protein: variable positivity in spindle cell component of sarcomatoid carcinoma

Other Techniques for Diagnosis

• Genetic studies of clinical relevance: Familial studies have demonstrated an 8q24 ( MYC oncogene) genetic variant that may be associated with prostate cancer risk; men with germline BRCA2 mutations have a 20-fold increased risk of prostate cancer; rearrangements of ETS family genes (most commonly ERG or ETV1 ) next to the androgen-regulated TMPRSS2 promoter has been identified as an early molecular event in the development of prostate cancer, illustrating the role of androgen stimulation in the pathogenesis of prostate cancer; testing for homologous recombination deficiency, particularly somatic or germline mutations of the homologous recombination repair genes ( BRCA1 , BRCA2 , and ATM ) predict response to poly(ADP-ribose) polymerase inhibitors in hormone refractory prostate cancer.

Differential Diagnosis

Clinical Features

• Patients may present with obstructive symptoms and hematuria

• Cystoscopy may show papillary proliferation distending prostatic urethra

Gross Pathology

• Prostatic ducts and prostatic urethra may be distended by tumor

Histopathology

• Invasive adenocarcinoma showing growth along prostatic ducts

• Papillary and cribriform architecture composed of pseudostratified (endometrioid-like) columnar cells with elongated nuclei

• Gleason pattern 4. Presence of comedonecrosis should be classified as Gleason pattern 5

Special Stains and Immunohistochemistry

• Basal cell markers negative

Other Techniques

• None

Differential Diagnosis

• PIN

  • Glandular proliferation less complex, glands less dilated, and basal cells may be attenuated but still present

• Acinar adenocarcinoma with cribriform architecture

  • Cuboidal (noncolumnar) cells with rounded nuclei creating rounded (nonelongated) cribriform spaces

Clinical Features

• Nothing specific

Gross Pathology

• Nothing specific

Histopathology

• Noninvasive carcinoma distending acini and/or ducts

• Architecturally may be solid, cribriform or micropapillary. Comedonecrosis may be present

Special Stains and Immunohistochemistry

• Noncontributory

Other Techniques

• Noncontributory

Differential Diagnosis

Clinical Features

• Serum PSA and PAP levels are typically not elevated

• Benign and malignant basal cell lesions are relatively uncommon (reported in less than 6% to 9% of cases); benign basal cell proliferations make up most of them

Gross Pathology

• Nonspecific

Histopathology

• Basal cell tumors consist of a spectrum of disease ranging from BCH to atypical BCH to basal cell adenoma to basal cell carcinoma (BCC); historically, a basal cell tumor with a cribriform architecture has been referred to as an adenoid basal cell tumor or adenoid cystic carcinoma (ACC); BCC and ACC are now considered parts of a morphologic continuum

Special Stains and Immunohistochemistry

• PSA and PAP typically positive

• HMWK: focal weak positivity in basaloid cells

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

Clinical Features

• Rarely occurs de novo; patients usually have a history of treated prostate cancer

• Most show no evidence of hormonal secretion; however, paraneoplastic syndromes (Cushing syndrome, hypercalcemia, syndrome of inappropriate antidiuretic hormone [SIADH] secretion and Eaton-Lambert syndrome) can occur

• May have minor elevations of serum PSA

• Metastasizes through hematogenous (liver, brain) rather than lymphatic channels

Gross Pathology

• Nonspecific

Histopathology

• Neuroendocrine differentiation seen in the following circumstances:

  • Conventional prostate adenocarcinoma frequently contains isolated cells positive for neuroendocrine markers only (not apparent on H&E [hematoxylin & eosin] slides)

  • Conventional prostate adenocarcinoma with a neuroendocrine component apparent on H&E slides

  • Conventional prostate adenocarcinoma with intermingled cells showing Paneth cell-like neuroendocrine differentiation

  • Carcinoid-like tumors (“well-differentiated neuroendocrine tumor”)

  • Small cell neuroendocrine carcinoma

  • Large cell neuroendocrine carcinoma

  • Post-therapy neuroendocrine differentiation (which some have designated “treatment-related neuroendocrine prostate cancer” or “Aggressive variant of prostate cancer”)

Special Stains and Immunohistochemistry

• Neuron-specific enolase (NSE), chromogranin, and cytokeratin typically positive

• PSA and PAP: often negative or only focally positive

• AMACR: 50% positive

• Secretory products may be present within neoplastic cells

• Adrenocorticotropic hormone (ACTH), serotonin, calcitonin, human chorionic gonadotropin (HCG), thyroid-stimulating hormone (TSH), and bombesin

Other Techniques for Diagnosis

• Electron microscopy: neuroendocrine cells contain round, regular membrane-bound neurosecretory granules, measuring 100 to 400 nm

Differential Diagnosis

Clinical Features

• Rare primary prostate gland tumor (represents 1% to 3% of primary prostatic gland malignancies)

• Common symptoms include hematuria or urinary obstruction

• PSA not elevated

• Three modes of prostatic involvement

  • Primary tumor of prostatic urethra, ducts, or acini

  • Secondary mucosal involvement from a prior or currently active bladder cancer

  • Direct invasion from bladder cancer infiltrating through the bladder wall

Gross Pathology

• Nodular proliferation in prostatic urethra

• Nonspecific nodular architecture with involvement of prostatic ducts and acini

Histopathology

• Carcinoma in situ (intraductal TCC) is typically present adjacent to the invasive component; may involve the urethra, the prostatic ducts and acini, and occasionally the ejaculatory ducts and seminal vesicles

• Infiltrative component consists of small groups or single cells with hyperchromatic, pleomorphic nuclei with chromatin clumping, multiple nucleoli, and angulated nuclear borders

• Mitotic figures and tumor necrosis are common

• Elicits a desmoplastic stromal reaction

• Pagetoid spread and squamous metaplasia may be seen

Special Stains and Immunohistochemistry

• HMWCK, CK7, and CK20 variably positive

• PSA and PAP negative

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

Clinical Features

• Rare in the prostate gland

• Typically found in older age group (mean age of about 70 years)

• Two clinical scenarios

  • Primary, de novo squamous cell carcinoma

  • Associated with treated (radiation or hormone ablation) adenocarcinoma

• Serum PSA and PAP are usually normal

• Metastatic bone lesions osteolytic, in contrast to adenocarcinoma, which causes osteoblastic bone lesions

• Most commonly associated with squamous cell carcinoma of the urinary bladder

• May be associated with Schistosoma haematobium infection

Gross Pathology ( Figure 11.8A )

• Nonspecific

Histopathology

• Similar histologic features to squamous cell carcinoma of other sites

• Malignant squamous cells arranged in cords and nests with an infiltrative architecture

• Two forms of carcinoma

  • Pure squamous carcinoma

    • Rare

    • Infiltrative growth pattern composed of malignant cells with squamous features (keratin formation and intercellular bridging) ( Figure 11.8B and C )

    • No gland formation

    • No patient history of radiation or hormonal therapy

    • Must exclude secondary involvement from extraprostatic sites (e.g., bladder)

  • Adenosquamous carcinoma

    • Admixture of adenocarcinoma and squamous cell carcinoma

    • Typically associated with a history of radiation or hormonal therapy

Special Stains and Immunohistochemistry

• PSA and PAP are positive in glandular component of adenosquamous carcinoma; pure squamous cell carcinoma is typically negative

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

Clinical Features

• Rare neoplasm

• Wide age range

• Patients present with symptoms associated with prostatic enlargement, which include urinary obstruction, hematuria, and dysuria

Gross Pathology

• Multinodular solid, gray-white mass

• Cut surface may be spongy or cystic

• Variable size; may be larger than 25 cm in diameter

Histopathology

• Biphasic tumor composed of epithelial and stromal components

• Epithelial cells are cuboidal to columnar, arranged in double-layer lining glands, cysts, or slitlike spaces

  • Stellate to spindle stromal cells arranged in a loose, myxoid background

• Glandular or cystic spaces compressed by cellular stroma into a leaflike configuration ( Figure 11.9 )

  

• Likelihood of recurrence and malignant behavior is associated with a high stromal to epithelial ratio (stromal hypercellularity), cellular atypia, and high mitotic rate

Special Stains and Immunohistochemistry

• Vimentin: stromal component is typically positive

• PSA and PAP: epithelial cells may be positive

• SMA negative

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

Clinical Features

• Most common sarcoma of the prostate

• Occurs primarily between birth and 6 years of age

• Most common in the head and neck, followed by the genitourinary tract

• About 20% of childhood cases occur in the genitourinary tract

• Rare cases reported in older men

• Presents with pelvic mass and urethral obstruction

• Pelvic mass may cause bladder displacement and rectal compression

Gross Pathology

• Large, gray-white mass typically measuring 5 to 10 cm

• Appears grossly circumscribed but is typically infiltrative microscopically

Histopathology

Special Stains and Immunohistochemistry

• Vimentin, MSA, desmin, and myoglobin positive

• Stains negatively for cytokeratin, LCA, NSE, PSA, and PAP

Other Techniques for Diagnosis

• Electron microscopy: rhabdomyoblasts have cytoplasmic myofilaments and Z bands

• Flow cytometry: tumor cells are typically aneuploid

Differential Diagnosis

• Must rule out metastasis from other primitive childhood small round blue cell tumors

• Non-Hodgkin lymphoma

• Typically found in older age groups

• Neoplastic lymphoid cells infiltrating stroma in diffuse sheets or patches; ducts and acini are typically spared

• Positive for LCA

• Composed of a monoclonal lymphoid population

Clinical Features

• Most common in older men (mean age, 60 years)

• Presents with urinary obstruction symptoms

• Primary lymphoma involves the prostate gland without extraglandular involvement (i.e., liver, spleen, lymph nodes, peripheral blood)

• Secondary involvement of the prostate gland by a systemic lymphoma is more common than primary prostate lymphoma

• Systemic symptoms (fever, chills, night sweats, and weight loss) are infrequent and typically seen only in patients with disseminated disease

Gross Pathology

• Diffuse enlargement of the prostate gland

• Tan, homogeneous, rubbery parenchyma

Histopathology

• Proliferation of neoplastic lymphoid cells that typically infiltrate the prostatic stroma in diffuse sheets while sparing the ducts and acini

• Infiltration into surrounding periprostatic tissues is common

• Most common subtype is diffuse large cell lymphoma, B-cell type; small cleaved cell lymphoma is also relatively common

• Hodgkin disease is rare

Special Stains and Immunohistochemistry

• LCA positive (non-Hodgkin lymphoma)

• Refer to Chapter 14 for specific immunohistochemistry profiles

Other Techniques for Diagnosis

• Flow cytometric immunophenotyping using fresh tissue is useful in documenting clonality and for subtyping lymphomas (refer to Chapter 14 )

Differential Diagnosis

Clinical Features

• Usually unilateral (75%)

• Occurs in 3% to 4% of term infants and in up to 20% of premature infants

• Undescended testicles typically descend by 3 months of age (<1% remain undescended at 1 year of age)

• Associated with an inguinal hernia in 10% to 20% of cases

• Most cryptorchid testes are found in the inguinal canal

• Right testicle is more commonly involved

• Patients with undescended and surgically descended cryptorchid testes have decreased fertility and increased risk for certain germ cell and non–germ cell tumors

• Normal descent of testes is under hormonal control

Gross Pathology

• Cryptorchid testes are smaller and softer than normal testes

Histopathology

• Histologic changes in cryptorchid testis occur by age 2 years

• Seminiferous tubules may be small or ring shaped and have areas of tubular sclerosis or atrophy ( Figure 11.10 )

  

• Spermatogonia may be decreased in number and irregularly distributed or totally absent

• Sertoli cells are increased in number; Leydig cell hyperplasia may be prominent

• Interstitium is typically widened and edematous

• Normally descended testis contralateral to the cryptorchid testis often shows many of the same histologic features

Special Stains and Immunohistochemistry

• Noncontributory

Differential Diagnosis

• Causes of testicular maldescent include anatomic abnormalities of the gubernaculum, hormonal dysfunction, mechanical impairment, and gonadal dysgenesis

Clinical Features

• Usually unilateral

• May be difficult to distinguish from cysts of paratesticular adnexa by ultrasound

Gross Pathology

• Albugineal cysts are usually uniloculated, centered in the visceral tunica albuginea, and contain clear fluid

• Epidermoid cysts are usually uniloculated, abut the visceral tunica albuginea; and contain laminated, granular, friable material ( Figure 11.11 )

  

• Rete testes cysts (cystic dysplasia of the rete testes) are usually multiloculated, retiform, centered in the testicular hilum, and contain clear fluid

Histopathology

• Albugineal cysts are at least partially lined by low cuboidal serosal epithelium

• Epidermoid cysts are lined by attenuated squamous epithelium, contain keratinaceous material, and, by definition, lack adnexal structures and germinal elements

• Rete testes cysts (cystic dysplasia of the rete testes) are lined by attenuated, low cuboidal epithelium

Special Stains and Immunohistochemistry

• Noncontributory

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

• Dermoid cysts are lined by keratinizing squamous epithelium but also have adnexal structures

• Teratomas may be mostly cystic lined by keratinizing squamous epithelium but also have teratomatous elements

Clinical Features

• Most are idiopathic; may be associated with inguinal hernia, scrotal trauma, orchitis, or testicular tumors

• May be secondary to congenital lack of closure of the processus vaginalis, resulting in a communication with the peritoneal cavity

• Characterized by accumulation of serous fluid between the parietal and visceral tunica vaginalis

• Occasionally patients present with acute testicular enlargement secondary to hemorrhage; lack of transillumination may necessitate orchiectomy

Gross Pathology

• Clear serous fluid-filled cavity compresses adjacent testis

• Hemorrhage or infection may cause fluid to become opaque

• Tunica may be thickened in long-standing lesions

Histopathology

• Fluid-filled cavity lined by flattened or cuboidal mesothelial cells

• Mesothelium may be hyperplastic or cytologically atypical

Special Stains and Immunohistochemistry

• Noncontributory

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

Clinical Features

Gross Pathology

• Acute: testicle is swollen and edematous

• Chronic: testicle is firm and often has a thickened tunica

Histopathology

Special Stains and Immunohistochemistry

• Stains for microorganisms can be useful to identify bacteria and fungi

Other Techniques for Diagnosis

• Noncontributory

Differential Diagnosis

Noninfectious Granulomatous Orchitis ( Figure 11.12 )

• Sarcoidosis

• Isolated (i.e., nonsystemic) testicular involvement is extremely rare

• Characterized by noncaseating granulomas composed of epithelioid histiocytes and giant cells

• Idiopathic granulomatous orchitis

• No organisms are identified

Clinical Features

• Typically presents with testicular enlargement with or without tenderness

• Often associated with chronic bacterial infections, particularly E. coli

• Rarely seen in children

Gross Pathology

• Testicular enlargement with focal areas of firm, tan-yellow tissue ( Figure 11.13A )