Case 003: 84 Year Old Female with Obstructive Nasopharyngeal Mass
Contributed by Andre Thompson, M.D. Supervised by Kimberly Mason, M.D.
An 84-year-old female has had bloody-mucous nasal discharge and increasing obstructive nasal symptoms, primarily on the right side. Nasal endoscopy in the office showed a hemorrhagic mass which filled the right nasal cavity, spilling over into the left posterior choana as well. A CT scan showed a 2-3 cm, polypoid posterior nasopharyngeal mass.
Intraoperative examination revealed a friable polypoid mass that appeared to originate from the posterior portion of the middle nasal turbinate dropping down into the nasopharynx and obstructing both sides of the nose, more on the right than the left.
The specimen consists of five (5) pink-tan, ragged, irregular, soft tissue fragments ranging from 0.5 x 0.5 x 0.2 up to 2.0 x 1.5 x 0.8 cm.
(Click a photo to view a larger image.)
Malignant melanoma. Routinely stained slides of the nasal mass show it to consist of a poorly differentiated malignant neoplasm. There is little evidence of specific differentiation; a faint brown pigmentation noted in some of the cells could have represented either melanin or hemosiderin on routinely stained slides. The differential diagnosis based on light microscopic examination would include almost any poorly differentiated neoplasm: undifferentiated carcinoma, sarcoma (especially olfactory neuroblastoma), lymphoma, or melanoma. Because of the presence of the brown pigment, we focused initially on ruling out melanoma. The results of the immunostains (S-100 positive, HMB-45 positive, Melan-A positive, vimentin positive, cytokeratin negative, synaptophysin negative) gave strong support to the diagnosis of malignant melanoma. The question would then arise whether this represents a primary tumor at this site or metastatic tumor from another site. As there is no definitive evidence of an in-situ component, metastatic melanoma cannot be entirely excluded; however, since this patient has no history of skin malignancy, it is more likely that this is a primary melanoma. Primary melanoma of the nasal cavity and paranasal sinuses comprises 1% of all malignant melanomas. The anterior septum, inferior turbinate and middle turbinate are the most frequent sites of origin within the nasal cavity. Treatment consists of complete excision; prognosis is poor, with 5-year survival around 10%.
Interestingly, the uninvolved tissue adjacent to the mass, which to the surgeon appeared dark in color, contained abundant melanin pigment associated with benign, non-atypical melanocytes. Melanosis may be seen in uninvolved tissues adjacent to a melanoma, though the significance of its presence in this case (i.e., whether it would be evidence for this tumor's being primary in this location) is unclear.
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