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Benign Cartilage Lesions

Traditionally, cartilage lesions are considered to be of neoplastic, dysplastic, hamartomatous, and reactive origin. Reactive cartilage containing lesions are described in Chapters 20 and 23 . Enchondroma is an example of a benign cartilage neoplasm that most frequently occurs within the medullary cavity. It rarely presents as a bone surface subperiosteal (juxtacortical) lesion such as a periosteal chondroma. Enchondromatosis is considered to represent a dysplastic cartilage…

Osteosarcoma

Osteosarcoma is the most common primary malignant tumor of bone. When all aspects of its presentation are taken into consideration, it is evident that this term is used to describe a heterogeneous group of lesions with diverse morphology and clinical behavior. From the morphologic point of view, osteosarcoma can be divided into several subgroups (e.g., osteoblastic, chondroblastic, fibroblastic). These terms reflect the great microscopic variability of…

Benign Osteoblastic Tumors

Benign osteoblastic tumors were first recognized as a distinct group by Jaffe and Mayer in 1932. The identification of osteoid osteoma as a separate entity came later in a 1935 report by Jaffe. Once osteoid osteoma had been established as a diagnostic category, other benign bone-forming lesions were recognized. The term benign osteoblastoma was introduced independently by Jaffe and Lichtenstein in 1956 to delineate a benign…

Molecular Biology of Bone Tumors

During the past two decades, our knowledge of the molecular events that are responsible for the development and progression of many human neoplasms, including those that affect the skeleton, has dramatically improved. This has been made possible by numerous technologic developments that have contributed to the understanding of cellular biology and that shed light on some molecular aspects of the malignant transformation of cells. The past…

Clinical Considerations and Imaging of Bone Tumors

Introduction Bone lesions lend themselves to radiographic assessment because of the fact that bone has a built-in contrast agent, the calcium hydroxyapatite crystal. Much information about bone destruction, bone production, matrix calcification and ossification, and the reactive response of the surrounding bone and periosteum is available from plain radiographs. Although other imaging techniques play a role in the diagnostic process, the plain film is still the…

General Considerations

Introduction The new edition of this book retains the conventional approach to the classification of bone tumors, dividing them into the categories of osteoblastic, chondroblastic, fibrous and fibroosseous, vascular and neurogenic, and others of mesenchymal tissue derivation. In general, the discussion of the lesions is similar but not identical to the World Health Organization's classification of bone tumors ( Table 1-1 ). The past decade has…

Dermatopathology

Hypertrophic lichen planus Differential diagnosis: Squamous cell carcinoma Clinical features Lichen planus is a T-cell–mediated autoimmune disease affecting the skin or mucosal surfaces. It has several clinical and pathologic variants, one of which is hypertrophic lichen planus (HLP). HLP typically occurs on the lower extremities, particularly the shins and the ankles. Unlike classic lichen planus which presents as flat-topped purple papules, HLP manifests as thick, hyperkeratotic,…

Mediastinum

Type A thymoma Differential diagnosis: Synovial sarcoma Clinical features Thymomas represent a morphologic spectrum of anterior mediastinal neoplasms derived from cortical and medullary epithelial cells of the thymus. They are typically encountered in the middle-aged patient; however, the age range at presentation is relatively broad. Thymoma can occur in the setting of myasthenia gravis and may rarely present with an accompanying pure red cell aplasia. Thymomas…

Lung

Squamous papilloma Differential diagnoses: Glandular papilloma, mixed squamous cell and glandular papilloma, and squamous cell carcinoma Clinical features Squamous cell papillomas account for less than 1% of lung neoplasms and are much less common compared with their incidence in the upper aerodigestive tract. However, they are the most common type of papilloma in the lung. Patients typically present with cough, wheezing, or hemoptysis. Up to 25%…

Endocrine pathology

Diffuse sclerosing variant of papillary thyroid carcinoma Differential diagnosis: Metastatic carcinoma Clinical features The diffuse sclerosing variant of papillary thyroid carcinoma (PTC) is recognized to exhibit specific clinical characteristics including female predominance and younger age at presentation (mean age, 18–29 years). Compared with classical PTC, this variant tends to be characterized by more aggressive biological behavior as evidenced by involvement of both thyroid lobes, extrathyroidal extension,…

Head and neck

Pleomorphic adenoma Differential diagnoses: Polymorphous adenocarcinoma & epithelial-myoepithelial carcinoma Clinical features Pleomorphic adenoma (PA), also called benign mixed tumor, is a benign tumor of the salivary glands. PAs are the most common salivary gland neoplasm and the vast majority occur in the parotid glands (∼80%) with lower incidence in submandibular glands (∼10%). PAs also arise in minor salivary glands of the upper aerodigestive tract (∼10%) with…

Soft tissue neoplasms

Adipocytic tumors Lipoma Differential diagnosis: Atypical lipomatous tumor/well-differentiated liposarcoma Clinical features Lipoma represents the most common mesenchymal soft tissue tumor of adults. Most commonly, lipomas are localized to the subcutaneous adipose tissue, presenting as a painless mass/swelling, although examples may arise in intramuscular locations and intrathoracic/intra-abdominal/retroperitoneal regions. If associated with peripheral nerves, there may be tenderness. Unlike ordinary lipomas, angiolipomas present as small and often painful…

Bone and joint

Diseases of joints Primary degenerative joint disease Differential diagnosis: Secondary degenerative joint disease of any cause Clinical features Primary degenerative joint disease (DJD) is the most common form of arthritis and causes progressively worsening pain, swelling, and lack of mobility in the affected joint, most often starting in the sixth and seventh decades when the reparative mechanisms can no longer keep pace with the degeneration of…

Breast

Complex sclerosing lesion/radial scar Differential diagnoses: Tubular carcinoma and low-grade adenosquamous carcinoma Clinical features Complex sclerosing lesions and radial scars (CSLs/RSs) are benign sclerosing lesions which may be encountered incidentally or as the targets of directed biopsies after imaging. Incidence varies depending upon the mode of detection, with most lesions today being identified by mammography. These sclerosing lesions account for 5% to 9% of cases in…

Genitourinary: Prostate, bladder, and kidney pathology

Prostate 1) Post-atrophic hyperplasia Differential diagnosis: Atrophic prostatic adenocarcinoma ( Table 5.1 ) Clinical features Post-atrophic hyperplasia (PAH) of the prostate is a benign lesion that may be encountered incidentally or as potential target of directed biopsies after MRI imaging. Typical mean age of presentation is 50, but can be seen at any age. PAH is typically encountered in the peripheral zone (PZ) compared with the…

Hepatobiliary and pancreas

Liver Hepatocellular tumors Focal nodular hyperplasia DDX: Hepatocellular adenoma, well-differentiated hepatocellular carcinoma, regenerative nodule Clinical features Focal nodular hyperplasia (FNH) is the most common benign hepatocellular tumor and is thought to represent a localized, regenerative proliferation of hepatocytes in an area of abnormal blood flow. While it most often affects women between 20 and 50 years, FNH can occur in either sex and in all age…

Neuropathology

Gliosis versus glioma Clinical features One of the most challenging differential diagnostic issues in surgical neuropathology is distinguishing between gliosis or reactive astrocytosis and an infiltrating low-grade glioma. Patients with low-grade gliomas may present at any age, although the peak is in the third through fifth decades of life. Often, patients present with signs or symptoms related to their tumor. Presentation is often tied to the…

Gynecologic tract

Classic (usual-type/HPV-associated) vulvar intraepithelial neoplasia Differential diagnoses: Differentiated (HPV-independent) vulvar intraepithelial neoplasia, invasive squamous cell carcinoma of the vulva, and Paget disease Clinical features The term vulvar intraepithelial neoplasia (VIN) describes non-invasive squamous lesions of the vulva, of which two major types exist—classic/usual-type VIN and differentiated/simplex-type VIN (DVIN). Usual-type/classic VIN typically occurs in reproductive age (premenopausal) women, whereas simplex-type/DVIN predominates in elderly (postmenopausal) women. Classic/usual-type VIN…

Gastrointestinal tract

Esophagus Gastroesophageal reflux esophagitis DDX: eosinophilic esophagitis, lymphocytic esophagitis, lichen planus, squamous dysplasia Clinical features Gastroesophageal reflux disease (GERD) is very common in Western countries, with a prevalence rate among adults in the United States estimated to be 20% to 40% based on symptomatology surveys. The etiology of GERD is reflux of gastric and/or duodenal contents (e.g., gastric acid, pepsin, bile, duodenal contents including pancreatic secretions)…

Infections of the Eye and Its Adnexa

The histopathologic study of infections of the eye and ocular adnexa is a daunting undertaking given the variety of tissues comprising this proportionately small area of the body with extensive exposure to the external environment. Only one previous summary of infections of the eyelid and conjunctiva has been published, but a broader conspectus combining extraocular and intraocular infections is not available. The term adnexa (plural noun,…