Recurrent Neuroendocrine Primary Cutaneous Mucinous Carcinoma of the Scalp After Complete Excision

Abstract

:Primary cutaneous mucinous carcinoma is a rare, indolent malignancy with a debated history regarding cell of origin. Recurrence is rare but has been documented in up to a third of cases. Recent literature reviews have recognized 2 possible subtypes—neuroendocrine and nonneuroendocrine— with different possible prognostic implications for patients. We describe a case of recurrent primary cutaneous mucinous carcinoma in a 50-year-old man with subtle neuroendocrine features not initially recognized on routine H&E staining but highlighted by immunohistochemical studies. We underscore the importance of immunohistochemical use in these rare cases and emphasize that awareness of these neuroendocrine and nonneuroendocrine subtypes is essential for a complete diagnosis.

Primary Mucinous Carcinoma of Skin: A Rare Cutaneous Neoplasm. Clinicopathologic Features, Differential Diagnoses, and Review of Literature

“…21 The cell of origin of the PMCS is still not fully established. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]19,48 Eccrine sweat glands are favored by some workers. [3][4][5]7,9,10 The ultrastructure of the differentiated cells of the neoplasm closely simulates the dark cells of the eccrine coil.…”

“…Histogenesis is still debated, and apocrine, eccrine, and neuroendocrine origins have been proposed. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] It commonly involves the periorbital region and presents as an asymptomatic, slow-growing, well-circumscribed mass that is often diagnosed as benign lesion. 18 Pathologically, these tumors may be mistaken for more common metastatic mucinous carcinomas; hence, immunohistochemical markers are essential for establishing a definite diagnosis.…”