Morphologically low-grade spiradenocarcinoma: a clinicopathologic study of 19 cases with emphasis on outcome and XXXX expression.

@entity1 @entity13327 @entity39 @entity5 @entity1489 @entity2347 @entity1066 @entity876 @entity3
UNASSIGNED: Spiradenocarcinoma is a @entity1489 with potential for aggressive behavior, classified histologically into low- and high-grade @entity5 . Morphologically, low-grade @entity5 are thought to behave more favorably. Limited information is available, however, with only 18 published cases. To study their clinical behavior, histological features, and the diagnostic value of immunohistochemistry, 19 morphologically low-grade spiradenocarcinomas were retrieved and compared with 21 spiradenomas and @entity2347 . H_E-stained sections were reviewed, follow-up was obtained, and immunohistochemistry for Ki-67, @entity876 and, @entity13327 was performed. The @entity5 were solitary, measuring 0.8-7   cm (median: 2.7   cm), with a predilection for the head and neck of elderly @entity1 (median age: 72 years; range 53-92) without gender bias. Histologically, the @entity5 were multinodular and located in deep dermis and subcutis. A pre-existing spiradenoma was present in all cases. The malignant component was characterized by expansile growth with loss of the dual cell population, up to moderate cytological atypia and increased mitotic activity (median: 10/10 HPF; range 1-28). Additional findings included squamoid differentiation (n=9), @entity39 (n=7), and @entity1066 (n=5). @entity876 expression was variable and no significant differences were noted in the benign compared with the malignant parts of the @entity5 . In contrast, in the malignant components the Ki-67 proliferative index was slightly increased, and @entity13327 expression was lost. Follow-up (median: 67 months; range: 13-132) available for 16 @entity1 (84%) revealed a local recurrence rate of 19% but no @entity3 or disease-related mortality. In this large study with long-term follow-up, we demonstrate that spiradenocarcinomas with low-grade morphology pursue an indolent course, characterized by local recurrence only. @entity3 and disease-related mortality appear to be exceptional. Lack of @entity13327 expression may be useful as an additional aid in the diagnosis of these challenging @entity5 .
