Browsing by Autor "Alejandro A. Gru"

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Histomorphological and immunophenotypical spectrum of cutaneous myoepitheliomas: A series of 35 cases
(Wiley, 2020) Jose A. Plaza; Thomas Brenn; Catherine Chung; Sadia Salim; Konstantinos Linos; George Jour; Juanita Duran Rincon; Mark R. Wick; Martín Sangüeza; Alejandro A. Gru
Myoepithelial tumors comprise a group of mesenchymal lesions that show heterogeneous histomorphological features, including dual epithelial, neural, and myoid differentiation. Cutaneous myoepithelioma is a rare neoplasm that is composed primarily of myoepithelial cells and represents one end of a histopathological spectrum of cutaneous myoepithelial neoplasms including chondroid syringoma and myoepithelial carcinoma. These tumors display a wide histopathological spectrum and immunophenotypical profile often showing epithelial and myoepithelial differentiation. In this series, we studied 35 cases of cutaneous myoepitheliomas. Our cases highlighted the broad histopathological range where most cases showed a non-infiltrative and non-encapsulated tumor exclusively located in the dermis and with no subcutaneous involvement. The majority of our cases had a solid growth pattern (syncytial pattern) and the remainder of cases had a multinodular growth pattern. The tumor cells were epithelioid in 23 cases, spindled in eight cases and there was a mixture of epithelioid and spindled cells in four cases. Mitotic figures ranged from 0 to 5 per 10 HPF. By immunohistochemistry epithelial membrane antigen (EMA) was expressed in 59% of cases S100 was positive in 88% of cases, CAM 5.2 was positive in 16% of cases, AE1/AE3 was positive in 44% of cases, p63 was positive in 17% of cases, smooth muscle actin was positive in 38% of cases, desmin was positive in 6% of cases, calponin was positive in 22% of cases, and glial fibrillary acidic protein was positive in 36% of cases. In addition, there were five cases without EMA, keratin, or p63 expression that only showed S100 expression. We describe a large series of cutaneous myoepitheliomas delineating their histomorphological spectrum and immunophenotypical profile. Awareness of some of the unusual histopathological features and the heterogeneous immunohistochemical may pose difficulties for the diagnosis.
Poorly differentiated cutaneous apocrine carcinomas: histopathological clues and immunohistochemical analysis for the diagnosis of this unusual neoplasm
(Wiley, 2022) Jose A. Plaza; Thomas Brenn; Alejandro A. Gru; Andrés Matoso; Jesse Sheldon; Martín Sangüeza
Primary cutaneous apocrine carcinoma (PCAC) is a rare cutaneous malignancy that is derived from apocrine glands. Histologically, these tumours can appear well-differentiated where diagnosis should be relatively straightforward. However, occasionally these tumours can exhibit high-grade features, and in such instances the diagnosis can be challenging. A retrospective analysis of 12 cases of poorly differentiated PCAC, obtained from large academic institutions, was performed, and summarised below. Immunohistochemical studies were performed in all cases with antibodies against CK7, p63, CAM 5.2, GCDFP-15, GATA3, CEA, PR, ER, HER2, calponin, SMA, androgen receptor and EMA. All 12 cases were poorly differentiated; however, there were some histopathological clues to the diagnosis of apocrine carcinoma; namely, the presence of focal glandular formation, acrosyringial involvement and the presence of single 'pagetoid' cells within epidermis. All tumours were consistently positive for CK7, GATA3 and GCDFP-15 and negative for p63. The tumours had variable expression of CAM5.2, CEA, ER, PR, HER2, androgen receptor and EMA. In three cases, there was a preservation of the myoepithelial cell layer (with calponin and SMA), which also confirmed the primary cutaneous origin. PCAC is a difficult neoplasm to diagnose, as it can appear identical to metastatic carcinomas. We describe 12 cases of poorly differentiated PCAC, highlighting their salient clinical, histopathological and immunohistochemical features, and discuss the potential diagnostic pitfalls in distinguishing this entity from other malignant neoplasms. Our results indicate that a combination of thorough histological inspection coupled with an adequate battery of immunohistochemical stains is necessary to support the diagnosis of PCAC.