Carcinoid-like pattern in sebaceous neoplasms: another distinctive, previously unrecognized pattern in extraocular sebaceous carcinoma and sebaceoma.

This report emphasizes a carcinoid-like pattern, a previously unrecognized feature in cutaneous sebaceous neoplasms. We report 7 patients with sebaceous tumors in which neoplastic cells were arranged in a trabecular and ribbon-like pattern or formed rosettes/pseudorosettes. The cases included 6 men and 1 woman, with their ages at the diagnosis ranging from 43 to 87 years (median age, 59). All patients presented with a solitary lesion. Locations were the scalp (n = 6) and forearm (n = 1). The carcinoid-like arrangement of neoplastic cells was the sole pattern in 4 cases, and in 3 cases the so-called labyrinthine/sinusoidal and/or rippled patterns were seen in addition. Sebaceous differentiation in the form of mature sebocytes varied from almost none to approximately 10%. Although the neoplasm appeared benign architecturally, the presence of cytologic atypia qualified 2 tumors as low-grade carcinomas. Four lesions represented sebaceomas, and in 1 case microscopic delineation between a carcinoma and sebaceoma was difficult. No neuroendocrine differentiation was demonstrated immunohistochemically, histochemically, and ultrastructurally. Electron microscopic examination performed in 1 case of carcinoma revealed lipid vacuoles in a minority of cells. There were no membrane-bound neuroendocrine granules. Rare cells contained peculiar large helioid inclusions. We conclude that the carcinoid-like pattern is another distinctive pattern indicative of sebaceous neoplasms. This pattern seems to be closely related to the rippled and labyrinthine/sinusoidal patterns, as exemplified by our cases, in which these arrangements sometimes occurred simultaneously.

Síndrome de Muir-Torre: relato de caso / Muir-Torre`s syndrome: case story

A associação de neoplasias de glândulas sebáceas e neoplasias viscerais múltiplas é característica da Síndrome de Muir-Torre. O objetivo deste estudo é apresentar o caso de paciente com múltiplos tumores de glândulas sebáceas associados a pólipo colônico, bem como discutir aspectos da doença. A associação de tumores cutâneos com pólipo adenomatoso do cólon e a história familiar de tumores viscerais foi diagnosticada em paciente de 55 anos inicialmente submetido à ressecção de lesões nodulares cutâneas. O resultado anatomopatológico evidenciou adenomas sebáceos, o que motivou a pesquisa de neoplasias viscerais, sendo que a colonoscopia mostrou lesão de 13 mm no ceco, cuja biópsia revelou adenoma túbulo-viloso. O paciente evoluiu com novas lesões de pele, que foram ressecadas sistematicamente até perfazerem um total de dez. Todas elas foram estudadas, confirmando neoplasias de glândulas sebáceas. Os exames realizados não detectaram outros tumores viscerais. A história familiar de neoplasias deste paciente inclui uma filha com rabdomiossarcoma retroperitoneal, a mãe com neoplasia de pulmão e uma irmã com leucemia. O achado de neoplasias de glândulas sebáceas deve levar à suspeita da Síndrome de Muir-Torre, devendo sempre ser seguida pela pesquisa de neoplasias viscerais.