Sine Qua Non: Oncocytoma.

Oncocytomas of the salivary gland are uncommon neoplasms that are characterized by polygonal cells with abundant granular eosinophilic cytoplasm and relatively uniform nuclei. They are benign in nature and have a low recurrence rate with complete surgical excision. Though uncommon, oncocytic and clear cell variants of malignant tumors may histologically mimic oncocytomas and identification of their distinguishing features is essential. A classic example of an oncocytoma is discussed.

Sine Qua Non: Dentigerous Cyst.

Dentigerous cysts, also known as follicular cysts, are among the most common developmental cysts of the gnathic bones. The majority of cases are clinically asymptomatic and discovered incidentally on panographic radiographs during routine dental care. The cyst appears as a radiolucency, classically unilocular, associated with the crown of an unerupted or impacted tooth. Usually diagnosed in the 2nd-3rd decade, third molars of the mandible are the most commonly affected teeth. Histologically, dentigerous cysts demonstrate a fibrous or fibromyxoid connective tissue wall lined by squamous epithelium, classically lacking rete ridges. Inflammation may introduce histologic changes, however. The differential diagnosis includes hyperplastic dental follicle, periapical or radicular cyst, unicystic ameloblastoma, odontogenic keratocyst, and other odontogenic cysts and tumors. While the findings are generally classic and pose no diagnostic dilemma, the diagnosis is best made in the context of the appropriate clinical and radiographic setting. Submitted tissue with a lack of history, to include a detailed relationship with the affected tooth, may result in misdiagnosis and subsequent confusion for the clinician. So, despite its simple features, dentigerous cysts are not uncommonly mischaracterized. Therefore a review of a classic case of dentigerous cyst is presented.

Sine Qua Non: Sinonasal Inverted Papilloma.

Inverted papilloma (IP) is a common proliferation of squamous epithelial cells of the sinonasal tract. Although considered benign, IP is known to cause local destruction, has a high rate of recurrence, and a low, but significant rate of malignant transformation. Differentiating an IP from its histologic mimickers is essential for appropriate risk stratification and long-term surveillance. A classic case of sinonasal inverted papilloma is discussed.

Laryngeal Contact Ulcer.

A 47-year-old man presented to the otolaryngology service with complaint of 6 months of intermittent globus sensation. He reported constant throat clearing and subjective lowering of his voice. Flexible nasolaryngoscopy revealed a large pedunculated mass originating from the left vocal process of the arytenoid, lying superior to the vocal fold. The patient was treated conservatively with an anti-reflux regiment and speech language therapy for 2 months, however he noted marginal worsening in voice over the proceeding interval with an increasing raspy quality. He underwent suspension microlaryngoscopy with biopsy. Microscopic examination demonstrated mucosal epithelium with surface ulceration and considerable fibrinoid necrosis, a mixed inflammatory infiltrate, and abundant granulation tissue with reactive endothelial cells. The diagnosis of laryngeal contact ulcer was rendered. The patient was treated with KTP (potassium titanyl phosphate) laser ablation and corticosteroid microinjection; he tolerated the procedures well and on follow-up noted reduced cough, improving voice quality and no residual dysphagia.

Reticular Oral Lichen Planus.

Reticular oral lichen planus is a common clinical finding, often found incidentally on routine oral examination. Patients rarely complain of symptoms and the condition does not require treatment, as a result, biopsies and ancillary laboratory evaluation are seldom performed. We present a case of reticular oral lichen planus with a classic clinical presentation and characteristic histologic findings.

Lymphangioma of the Dorsal Tongue.

Lymphangiomas are rare, congenital malformations of the lymphatic system which have a marked predilection for the head and neck. In this region, they most commonly occur on the dorsum of the tongue, followed by the lips, buccal mucosa, soft palate, and floor of the mouth. Lymphangiomas of the tongue are commonly present at birth; however, they may go unnoticed until after eruption of the dentition or even puberty. They may present as a defined mass or as macroglossia with impaired speech, difficulty in mastication, and, in extreme cases, airway obstruction. Clinically, lymphagiomas of the tongue are characterized by clusters of pebbly, vesicle-like nodules. A benign proliferation of lymphatic vessels is identified histologically. A classic case of a lymphangioma of the dorsal tongue is presented.

Benign Fibro-Osseous Lesions of the Head and Neck.

Benign fibro-osseous lesions (BFOLs) are a particularly challenging set of diagnoses for the pathologist. This diverse collection of diseases includes fibrous dysplasia, ossifying fibroma and cemento-osseous dysplasia. While all three conditions have similar microscopic presentations, their treatment and prognosis differ, demanding an accurate and definitive diagnosis. A practical and systematic approach considering the patient's history, demographics, intraoperative presentation, and gross appearance with an emphasis on radiology and histology will be discussed.

Squamous Cell Papillomatosis in the Setting of Recurrent Respiratory Papillomatosis.

A 23 year old male presented to the Otolaryngology clinic with 6 months of hoarseness and poor voice projection without improvement from speech therapy or medical anti-reflux medication. Upon examination he was found to have multiple polypoid lesions emanating from bilateral false vocal folds, left true vocal fold, and the anterior commissure. Biopsy and potassium titanyl phosphate (KTP) laser ablation with bevacizumab injection provided treatment and confirmed the clinical suspicion of squamous cell papilloma. Despite 3 years of treatment, the papillomatosis proved difficult to control, requiring a procedure approximately every 3 months. In an attempt to control the course of the disease the patient received a series of three bevacizumab and three cidofovir injections. Serial biopsies showed mild atypia within the squamous cell papillomas. Two separate biopsies confirmed presence of human papillomavirus (HPV) 6/11 via in situ hybridization with appropriate controls. There is promising research that the quadrivalent HPV (types 6, 11, 16, and 18) vaccine both reduces the disease burden in patients with active disease and reduces the incidence of recurrent respiratory papillomatosis (RRP). Other studies have shown that local immunologic dysregulation may play a role in RRP pathogenesis. Therefore new treatment options, to include PDL-1 blockade, offer hope in treating this benign condition with high morbidity and rare mortality.

Oral Histoplasmosis.

A 44-year-old female presented to her general dentist with the chief complaint of a painful mouth sore of 2 weeks duration. Clinical examination revealed an irregularly shaped ulcer of the buccal and lingual attached gingiva of the anterior mandible. A biopsy was performed and microscopic evaluation revealed histoplasmosis. Histoplasmosis, caused by Histoplasma capsulate, is the most common fungal infection in the United States. Oral lesions of histoplasmosis are generally associated with the disseminated form of histoplasmosis and may present as a fungating or ulcerative lesion of the oral mucosa. The histologic findings and differential diagnosis for oral histoplasmosis are discussed.

Embryonal Rhabdomyosarcoma of the Oral Cavity.

A 19 year old female presents to the emergency room with right facial enlargement. Clinical examination revealed a soft tissue mass of the right buccal mucosa. Treated initially as infection, the patient later turned to clinic with now rapidly enlarging and intermittently painful mass. Computed tomography with contrast showed a low attenuated buccal mass with mild enhancement lateral to the right caudal maxilla and superior mandible. Biopsy was performed and microscopic examination showed cells with moderate pleomorphism with numerous atypical mitotic figures and occasional elongated "strap" cells with eccentric nuclei. Fluorescence in situ hybridization analysis revealed no rearrangement of the FKHR gene. The diagnosis of embryonal rhabdomyosarcoma was rendered. The patient was referred to the local children's hospital for definitive treatment.

Oral Secondary Syphilis.

Secondary syphilis develops in approximately 25% of patients infected with the spirochete bacterium Treponema pallidum. It typically develops several weeks to several months after the primary infection, which is recognized by a painless chancre. Secondary syphilis is characterized by systemic symptoms, such as malaise and fever as well as a maculopapular rash involving the trunk and extremities including the palms and soles. Condyloma lata, which are raised, fleshy lesions, tend to develop at the site of the primary chancre. Diagnosis is achieved primarily through screening and confirmational serologic testing. Histologic findings seen in condyloma lata are largely non-specific. Therefore, a high index of suspicion should be maintained and immunohistochemical stains specific for T. pallidum should be utilized.

Dermoid Cyst of the Floor of the Mouth.

A case of a dermoid cyst of the floor of mouth affecting a 19 years old male will be discussed. The macroscopic and histologic findings used for diagnosis will be covered. The typical features of this type of cyst will also be reviewed including radiographic and histologic findings. Discussion will include etiology and usual presentation, as well as treatment.

Allergic Fungal Sinusitis.

A 42 year old male presents with worsening pain and an increase in thick chronic drainage of the left sinus. Image studies show complete opacification of the left frontal sinus, left sphenoid sinus, and the left maxillary sinus. The patient was taken to the operating room and tissue for microscopic evaluation was obtained. The microscopic findings were classic for allergic fungal sinusitis: areas of alternating mucinous material and inflammatory cell debris and abundant Charcot-Leyden crystals. Cultures were performed and the patient began steroid therapy and desensitization therapy.

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.

Ameloblastic fibro-odontoma.

A case of an amelobastic fibro-odontoma affecting a 15 year-old girl will be discussed. The characteristic radiologic and histologic features of the entity will be described.

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.

Sinonasal tract mucoepidermoid carcinoma: a clinicopathologic and immunophenotypic study of 19 cases combined with a comprehensive review of the literature.

Primary sinonasal tract mucoepidermoid carcinomas (MEC) are uncommon tumors that are frequently misclassified, resulting in inappropriate clinical management. The design of this study is retrospective. Nineteen cases of MEC included 10 females and 9 males, aged 15-75 years (mean, 52.7 years); males, on average were younger by a decade than females (47.2 vs. 57.7 years). Patients presented most frequently with a mass, obstructive symptoms, pain, and/or epistaxis present for a mean of 12.6 months. The majority of tumors involved the nasal cavity alone (n=10), maxillary sinus alone (n=6), or a combination of the nasal cavity and paranasal sinuses (n=3) with a mean size of 2.4 cm. Most patients presented at a low clinical stage (n=15, Stage I & II), with only 4 patients presenting with Stage III disease. Histologically, the tumors were often invasive (bone or perineural invasion), with invasion into minor mucoserous glands. Surface involvement was common. The neoplastic cells were composed of a combination of squamoid cells, intermediate cells, and mucocytes. Cystic spaces were occasionally large, but the majority were focal to small. Pleomorphism was generally low grade. Necrosis (n=5) and atypical mitotic figures (n=6) were seen infrequently. Over half of the tumors were classified as low grade (n=11), with intermediate (n=4) and high grade (n=4) comprising the remainder. Mucicarmine was positive in all cases tested. Immunohistochemical studies showed positive reactions for keratin, CK5/6, p63, CK7, EMA, and CEA in all cases tested, while bcl-2 and CD117 were rarely positive. GFAP, MSA, TTF-1, and S100 protein were non-reactive. p53 and Ki-67 were reactive to a variable degree. MEC need to be considered in the differential diagnosis of a number of sinonasal lesions, particularly adenocarcinoma and necrotizing sialometaplasia. The patients were separated into stage I (n=9), stage II (n=6), and stage III (n=4), without any patients in stage IV at presentation. Surgery occasionally accompanied by radiation therapy (n=2) was generally employed. Six patients developed a recurrence, with 5 patients dying with disease (mean, 2.4 years), while 14 patients are either alive (n=9) or had died (n=5) of unrelated causes (mean, 14.6 years). MEC probably arises from the minor mucoserous glands of the upper aerodigestive tract, usually presenting in patients in middle age with a mass. Most patients present with low stage disease (stage I and II), although invasive growth is common. Recurrences develop in about a third of patients, who experience a shorter survival (mean, 6.5 years). The following parameters, when present, suggest an increased incidence of recurrence or dying with disease: size ≥ 4.0 cm (P=0.034), high mitotic count (P=0.041), atypical mitoses (P=0.007), mixed anatomic site (P=0.032), development of recurrence (P=0.041), high tumor grade (P=0.007), and higher stage disease (P=0.027).