[494] Primary Cutaneus Adenoid Cystic Carcinoma: Histological and Immunohistochemical Findings in a Series of 25 Cases

Angel Santos-Briz, Mar Llamas, Laia Curto, Thomas Mentzel, Arno Rutten, Heinz Kutzner. Hospital Universitario de Salamanca, Salamanca, Spain; Hospital Universitario de la Princesa, Madrid, Spain; Hospital del Mar, Barcelona, Spain; Dermatopathologische Gemeinschaftspraxis, Friedrichshafen, Germany

Background: Primary cutaneous adenoid cystic carcinomas (PCACCs) are rare adnexal tumors, with less than 60 cases reported to date. They are defined as low-grade neoplasms of uncertain histogenesis, characterized by a cribiform pattern, frequent perineural invasion and repeated local recurrences.
Design: A series of 25 cases of PCACCs from the archives of the authors were analyzed to further characterize the pathologic spectrum and immunohistochemical features of this entity.
Results: Fifteen patients were female (60%) and 10 were male (40%), with age at presentation ranging from 40 to 86 years (median, 60 y). Tumors were located mostly in the head (29%), trunk (24%) and upper extremities (24%). All tumors showed poor circumscription and were composed of a bipopulation of duct-type epithelial cells lining true lumina, and myoepithelial basaloid polygonal cells disposed adjacent to the basement membrane in peripheral, abluminal distribution. Most cases showed a cribiform pattern, admixed with tubular structures (12 cases, 48%), nodular areas (3 cases, 12%) or both (6 cases, 24%). One case exhibited a pure tubular pattern. 7 cases (28%) showed perineural infiltration. The depth of the tumors could be assessed in 17 cases, and ranged from 2.2 to 9.5mm (median, 5.5mm). Most tumors infiltrated the subcutis. The dimorphic tumor cell population was well appreciated with immunohistochemistry. In all cases epithelial cells stained with CD117, and in 23 cases (92%) with CK7. Basaloid myoepithelial cells stained in all cases with actin and in 21 cases (84%) with p63.
Conclusions: Our findings indicate that PCACCs show similar histologic and immunohistochemical features to ACCs of other locations. The expression of CD117 in the epithelial component, and the demonstration of myoepithelial cells could help in the differential diagnosis with other neoplasms, mainly ACC-like basal cell carcinoma.
Category: Dermatopathology

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 62, Wednesday Morning

 

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