Brenda L. Nelson

Keratocystic odontogenic tumor.

The keratocystic odontogenic tumor is a benign developmental tumor with many distinguishing clinical and histologic features. These characteristics are reviewed in the setting of a typical presentation. The newly acknowledged neoplastic potential and its implications for treatment strategies are also discussed.

Ceruminous adenomas: A clinicopathologic study of 41 cases with a review of the literature

Background:Ceruminous gland neoplasms are rare neoplasms. To date, a large clinicopathologic study of benign ceruminous gland neoplasms has not been reported. Design:Forty-one cases of ceruminous gland adenomas diagnosed between 1970 and 2000 were retrieved from the files of the Armed Forces Institute of Pathology. Histologic features were reviewed, immunohistochemical analysis was performed (n = 21), and patient follow-up was obtained (n = 40). Results:The patients included 22 men and 19 women, 24 to 85 years of age (mean, 54.2 years). Patients presented clinically with a painless mass of the outer half of the external auditory canal (n = 33) or with hearing changes (n = 11). Symptoms were present for an average of 16.3 months. The polypoid masses affected the external auditory canal only and ranged in size from 0.4 to 2 cm in greatest dimension (mean, 1.1 cm). Histologically, the tumors demonstrated glands and small cysts lined by a tubuloglandular proliferation of inner ceruminous cells (cerumen-secreting epithelium with decapitation secretion) subtended by a spindled to cuboidal myoepithelial layer. A hyalinized stroma created an infiltrative pattern of growth; surface involvement (n = 8) was seen. Tumors were divided into ceruminous adenoma (n = 36), ceruminous pleomorphic adenoma (n = 4), and syringocystadenoma papilliferum (n = 1) types. The luminal cells were strongly and diffusely immunoreactive with CK7, while the basal cells were highlighted with CK5/6, S-100 protein, and p63. CD117 highlighted the luminal cells preferentially. The proliferation markers revealed a low index. Adenocarcinoma and middle ear adenoma are the principal differential consideration. Surgical excision was used in all patients. Four patients developed a recurrence due to incomplete excision. All patients were without evidence of disease at the last follow-up: alive (n = 28, mean 16.3 years) or dead (n = 12, mean 11.8 years). Conclusion:Ceruminous gland adenomas are the most common external auditory canal tumors. They demonstrate a dual cell population of basal myoepithelial-type cells and luminal ceruminous (ceruminal) cells. Cerumen pigment, CK7, and p63 can help to distinguish this tumor from other neoplasms that occur in the region. Complete surgical excision results in an excellent long-term clinical outcome.

Central Giant Cell Lesion

A classic case of central giant cell lesion (CGCL) is presented with emphasis on clinical, radiologic, and histologic features. The differential is discussed including peripheral giant cell granuloma, brown tumor of hyperparathyroidism, and giant cell tumor of bone. The molecular pathway of osteoclastogenesis is selectively reviewed and applied to suggest possible etiologies of the giant cell lesions. CGCL syndromes and treatment are also discussed.

Nasopalatine Duct Cyst

A case of a nasoplatine duct cyst in a 41-year-old male is reviewed. The typical radiologic and histologic findings are presented.

External Auditory Osteoma

External auditory canal (EAC) osteomas are rare, benign bony neoplasms that occur in wide range of patients. While chronic irritation and inflammation have been suggested as causal factors in several cases, significant data is lacking to support these suspicions. Symptoms are rare and can include hearing loss, vertigo, pain and tinnitus. Diagnosis is made based on a combination of clinical history and examination, radiographic imaging, and histopathology. Osteomas of the EAC are usually found incidentally and are unilateral and solitary. Computed tomography reveals a hyperdense, pedunculated mass arising from the tympanosquamous suture and lateral of the isthmus. Histopathologically, EAC osteomas are covered with periosteum and squamous epithelium, and consist of lamalleted bone surrounding fibrovascular channels with minimal osteocysts. Osteomas have historically been compared and contrasted with exostoses of the EAC. While they share similarities, more often than not it is possible to distinguish the two bony neoplasms based on clinical history and radiographic studies. Debate remains in the medical literature as to whether basic histopathology can distinguish osteomas of the EAC from exostoses. Surgical excision is the standard treatment for EAC osteomas, however close observation is considered acceptable in asymptomatic patients.

Langerhans Cell Histiocytosis of the Temporal Bone

Histologic examination of hematoxylin and eosin stained slides demonstrated a collection of histiocytes with associated eosinophils, lymphocytes, plasma cells and isolated multinucleated cells (Fig. 2). The lobular, indented and folded nuclei were surrounded by a microvacuolated clear to eosinophilic cytoplasm. The nuclear chromatin was finely basophilic. Focal eosinophilic microabscesses were noted. Immunohistochemical stains showed S-100 protein and CD1a strong cytoplasmic immunoreactivity.

Solitary Bone Cyst

A classic solitary bone cyst is discussed. Radiology and histology is reviewed.

Alveolar Rhabdomyosarcoma of the Paranasal Sinuses

Disclaimer The opinions and assertions expressed herein are those of the author and are not to be construed as official or representing the views of the Department of the Navy or the Department of Defense.

Nonkeratinizing Undifferentiated Nasopharyngeal Carcinoma

Microscopic examination of a biopsy of the nasopharyngeal mass demonstrated multiple nests of round cells with a syncytial growth pattern, prominent nucleoli, scant cytoplasm with nuclear overlap, and an absence of keratinization (Figs. 2, 3). Immunohistochemical stains for AE1/AE3, CAM 5.2, and epithelial membrane antigen (EMA) were positive, while p16 was negative. Furthermore, the tissue was strongly reactive for Epstein–Barr virus encoded RNA (EBER) by in situ hybridization (Fig. 4).

Juvenile Active Ossifying Fibroma

A case of juvenile active ossifying fibroma affecting a 27 year-old man will be discussed. The characteristic radiologic and histologic features of the entity will be described.