Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Benign Neoplasms of the Ear and Temporal Bone

▪ Ceruminous Adenoma Ceruminous adenoma is a benign glandular neoplasm of ceruminous glands (modified apocrine sweat glands) that arises solely from the external auditory canal (EAC). Clinical Features Ceruminous Adenoma—Disease Fact Sheet Definition ▪ Benign ceruminous gland neoplasm Incidence and Location ▪ Rare ▪ Outer half of the external auditory canal Morbidity and Mortality ▪ None Sex and Age Distribution ▪ Equal sex distribution ▪ Wide…

Non-Neoplastic Lesions of the Ear and Temporal Bone

▪ First Branchial Cleft Anomalies First branchial cleft anomalies include a spectrum of benign congenital fistulas, sinuses, and cysts and result from incomplete fusion of the first and second branchial arches, with persistence of the ventral component of the first branchial cleft. The first branchial cleft gives rise to the external auditory canal, whereas the first branchial arch gives rise to the mandible, muscles of mastication,…

Malignant Neoplasms of the Gnathic Bones

■ Osteosarcoma Osteosarcoma (OS) is defined as a group of malignant tumors whose neoplastic cells produce bone. It is the most common primary malignant bone tumor. Aggressive behavior is usually associated with high-grade morphology of the atypical osteoid-producing osteoblasts. Tumors of the jaw are the fourth most common site of OSs, accounting for approximately 6% of all OSs. Other sites are paranasal sinuses and skull base.…

Benign Neoplasms of the Gnathic Bones

■ Ossifying Fibroma Ossifying fibroma is a benign neoplasm that falls in to the broader category of benign fibro-osseous lesions (BFOLs). All BFOLs are characterized by the replacement of native bone by fibrous and mineralized tissues and are grouped together due to their histologic similarities despite having different clinical features and treatments. The other BFOLs, fibrous dysplasia and the cemento-osseous dysplasias, can be difficult to differentiate…

Non-Neoplastic Lesions of the Gnathic Bones

■ Osteomyelitis Osteomyelitis (osteitis) is an inflammatory or infectious process in the marrow cavities of the bone. It may be either acute or chronic. There are many classification schemes, including composition of the infiltrate (acute, subacute, chronic, granulomatous), infectious agent (bacteria, fungi, virus), method of acquisition (hematogenous, direct extension, or contamination), and site of involvement. It originates as inflammation of the bone marrow connective tissue or…

Malignant Neoplasms of the Salivary Glands

■ Mucoepidermoid Carcinoma Clinical Features Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumor (12% to 29%). Over half of all cases involve major glands, particularly the parotid ( Fig. 13.1 ). Other sites include the mouth, particularly the palate ( Fig. 13.1 ), buccal mucosa, lips, retromolar trigone, and the upper and lower respiratory tracts. Rarely, intrabony tumors form in the mandible and…

Benign Neoplasms of the Salivary Glands

▪ Pleomorphic Adenoma Pleomorphic adenoma (PA), also called benign mixed tumor or mixed tumor, is a benign salivary gland neoplasm composed of ductal epithelial and myoepithelial cell proliferations set within a mesenchymal stroma. This tumor displays remarkable histomorphologic diversity, including varying cellularity, cell morphology, matrix type, and encapsulation. Clinical Features Pleomorphic Adenoma—Disease Fact Sheet Definition ▪ A benign neoplasm composed of ductal epithelial cells and myoepithelial…

Non-Neoplastic Lesions of the Salivary Glands

■ Developmental Lesions, Including Heterotopia and Oncocytosis Salivary glands are composed of three paired major glands—the parotid, submandibular, and sublingual—and approximately 1000 minor seromucous glands that are distributed throughout the sinonasal tract, oral cavity, pharynx, larynx, and lower respiratory tract. The minor salivary glands secrete continuously, whereas the major glands secrete mainly in response to parasympathetic activity induced by stimuli. All the glands develop from ingrowths…

Malignant Neoplasms of the Oropharynx

▪ Squamous Cell Carcinoma Squamous cell carcinoma (SCC) arises not only from the surface epithelium of the oropharynx but also from the tonsillar crypts. It is steadily increasing in incidence due to high-risk human papillomavirus (HPV), and HPV-positive oropharyngeal SCC is a biologically and clinically distinct type of head and neck cancer. Clinical Features SCC constitutes the majority of oropharyngeal malignancies (> 90%). Most develop in…

Malignant Neoplasms of the Oral Cavity

▪ Squamous Cell Carcinoma Clinical Features Squamous Cell Carcinoma—Disease Fact Sheet Definition ▪ A malignant neoplasm arising from the mucosal epithelium of the oral cavity ▪ Related to incidence and location ▪ Most common malignancy of the oral cavity (> 90%) ▪ More than 48,000 cases diagnosed in the United States each year (includes oropharynx) ▪ Most commonly arises from the tongue (lateral border and ventral),…

Benign Neoplasms of the Oral Cavity

■ Fibroma The term fibroma, unless further qualified (e.g., ossifying fibroma, ameloblastic fibroma), refers to a localized proliferation of fibrous connective tissue in response to tissue irritation. As such, oral fibromas are reactive in nature, with some advocating the use of alternative designations, such as “traumatic fibroma” or “irritation fibroma.” It is believed that these terms more accurately reflect the true reactive nature of this lesion,…

Non-Neoplastic Lesions of the Oral Cavity

■ Fordyce Granules Clinical Features Fordyce granules are considered benign ectopic sebaceous glands (not associated with hair follicles) that occur on the oral mucosa. A normal variant, they are reported in up to 80% of adults, most commonly on the upper and lower lip and the buccal mucosa. They present as multiple, uniform-sized yellow or yellow-white papules ( Fig. 7.1 ), which may coalesce to form…

Malignant Neoplasms of the Larynx, Hypopharynx, and Trachea

▪ Precursor Squamous Lesions Precursor lesions are difficult to define because they have an increased likelihood of progressing to squamous cell carcinoma (SCC). A constellation of architectural and cytologic features constitute dysplasia, but these features are not uniformly accepted or understood, thereby leading to differences in intra- and interobserver interpretation. It is wise to use the term atypia in the context of reactive, inflammatory, or regenerative…

Benign Neoplasms of the Larynx, Hypopharynx, and Trachea

■ Squamous Papillomas Squamous papillomas are the most common benign neoplasms of the larynx and trachea, characterized by an exophytic squamous epithelium lining branching fibrovascular cores, often associated with human papillomavirus (HPV) infection. They may be solitary or may present in the setting of recurrent respiratory papillomatosis (RRP), a disorder characterized by numerous, multifocal, recurrent benign squamous papillomas of the respiratory tract. Squamous papillomas have a…

Non-Neoplastic Lesions of the Larynx, Hypopharynx, and Trachea

▪ Vocal Cord Polyps and Nodules Vocal cord polyps and nodules represent reactive changes of laryngeal mucosa and adjacent stroma that result in a benign polypoid or nodular growth. The etiology is multifactorial, including laryngeal trauma (accidents or surgery), excessive and improper use of voice (vocal abuse), iatrogenic or functional lesions, infection, hypothyroidism, and smoking. Clinical Features Vocal Cord Polyps and Nodules—Disease Fact Sheet Definition ▪…

Malignant Neoplasms of the Nasal Cavity, Paranasal Sinuses, and Nasopharynx

Malignant tumors of the sinonasal tract (SNT) are rare, comprising less than 1% of all neoplasms and about 3% of those of the upper aerodigestive tract. Squamous cell carcinoma (SCC) and adenocarcinoma are strongly associated with environmental factors, including the use of tobacco and alcohol and occupational exposures, such as heavy metal particles (nickel, chromium) and the leather, textile, furniture, and wood industries. SNT malignancies most…

Benign Neoplasms of the Nasal Cavity, Paranasal Sinuses, and Nasopharynx

▪ Sinonasal Papillomas The mucosa of the nasal vestibule and the superior wall of the nasal cavity are lined by squamous and olfactory mucosa, respectively. The remaining nasal mucosa consists of ciliated columnar epithelium of ectodermal origin known as the schneiderian membrane. Three benign neoplastic papillomatous proliferations arise from the schneiderian membrane: inverted or endophytic papillomas (IP; most common), exophytic, fungiform, or everted papillomas (EPs; second…

Non-Neoplastic Lesions of the Nasal Cavity, Paranasal Sinuses, and Nasopharynx

■ Rhinosinusitis Rhinosinusitis is defined simply as inflammation of the nasal cavity (rhinitis), paranasal sinuses (sinusitis), or both (rhinosinusitis). Clinical Features Rhinosinusitis is a common condition that can be caused by myriad etiologies, including allergies (most common), infections, aspirin intolerance, exposures to toxins or medications, pregnancy, systemic diseases, among others. Rhinosinusitis can also be idiopathic, with no known cause. Regardless of etiology, patients share the symptoms…

Issues in Laboratory Animal Science That Impact Toxicologic Pathology

1 Introduction As an integral member of the preclinical study team, the toxicologic pathologist needs to have a thorough understanding of the laboratory animal model that serves as a test system for studies with pathology requirements. Genetic, microbial, experimental, and environmental factors greatly affect lesion development in laboratory animals, and an understanding of the interplay of these factors with test article–induced effects is necessary for the…

Practices to Optimize Generation, Interpretation, and Reporting of Pathology Data from Toxicity Studies

1 Introduction Toxicologic pathologists fill important roles in enabling the delivery of new medicines, chemicals, and other products that improve and save lives across the world. These include serving as study pathologists, peer review pathologists, sponsor pathologists, consultants, toxicologists, and other roles. For many pathologists, postgraduate training is just the beginning of a journey of professional growth practicing toxicologic pathology at a diverse group of organizations…