Warthin-like variant of mucoepidermoid carcinoma of the parotid gland

@#A 57-year-old woman with a 2-year history of a left infra-auricular mass with no associated symptoms presented with a 6.0 cm ´ 4.0 cm ´ 3.0 cm firm, non-tender, movable mass. No imaging was done. Fine needle aspiration biopsy (FNAB) revealed sheets of epithelial cells that had abundant dense grayish-blue cytoplasm in a mucinous background with abundant lymphocytes (Figure 1), suggestive of salivary gland neoplasm with oncocytic or oncocytoid features (Category IVB, Salivary Gland Neoplasm of Uncertain Malignant Potential).Total parotidectomy revealed a 4.3 X 3.2 X 3.0 cm deep lobe lesion with a tan-grey to dark brown, smooth and dull external surface. Cut sections showed a cream-white to pink, lobulated, heterogenous cut surfaces. Microscopically, the lesion was unencapsulated with poorly demarcated borders. The neoplastic cells were arranged in haphazard sheets and surrounded by abundant lymphocytes. The tumor cells had abundant eosinophilic and granular cytoplasm compatible with oncocytes with mild to moderate nuclear atypia. There were occasional cystic spaces that contained mucin though mucocytes were not readily apparent. (Figure 2) Necrosis, perineural and lymphovascular space invasion or anaplasia were not evident.

Sinonasal tract meningioma

@#A 63-year old Filipino female presented with epistaxis of undisclosed duration. Examination showed a vascular, pulsating, rubbery intranasal mass involving both nasal cavities. The clinical impression was that of a nasal hemangioma. She underwent excision of the tumor and the specimen was sent for histopathologic evaluation. The specimen consisted of several tan-brown irregular tissue fragments with an aggregate diameter of 2 cm. Microscopic examination showed a cellular spindle cell tumor underneath the respiratory mucosa. (Figure 1) The tumor cells formed a syncytial pattern arranged in whorls that were separated by thin fibrovascular bands. (Figure 2) The cells had round to oval nuclei with nuclear clearing and moderate amount of syncytial cytoplasm compatible with a meningothelial derivation. (Figure 3) There was absence of nuclear atypia, significant mitotic activity, and necrosis. Immunohistochemistry studies showed positivity for Epithelial Membrane Antigen (EMA) and Progesterone Receptors (PR), and absence of reaction for Smooth Muscle Actin (SMA) and CD34. (Figure 4) Our diagnosis was sinonasal tract meningioma. Primary extracranial meningioma of the sinonasal cavity is rare and thus secondary extension from a primary intracranial tumor should be ruled out. It involves a wide age range with no striking gender predilection.1,2 Most common symptoms include nasal obstruction, epistaxis, exophthalmos, and a mass. Etiogenesis is not completely established and is postulated to arise from meningocytes that are entrapped during closure of midline structures, very similar to the development of meningoceles.3 Histopathologic examination discloses a spindle cell tumor arranged predominantly in whorls composed of cells showing meningothelial differentiation. Most are histologically grade 1 tumors. Grade 2 and 3 sinonasal tract meningiomas are rare.4 Histologic differential diagnoses include a glomangiopericytoma, leiomyosarcoma, and a solitary fibrous tumor/hemangiopericytoma. Close histologic evaluation with appropriate immunohistochemistry studies point to the correct diagnosis. Meningioma shows strong diffuse positivity with EMA and PR, and is usually negative for other immunohistochemistry markers such as muscle actins (for glomangiopericytoma and leiomyosarcoma), and CD34 (for solitary fibrous tumor/hemangiopericytoma).1,3 A diagnosis of primary sinonasal meningioma should not be made if an intracranial mass is identified.4 Sinonasal meningiomas are benign tumors with no documented distant metastases.1,2 Although recurrences occur in about 30% (mostly due to incomplete excision), metastasis and malignant transformation has not been reported.