HER2 testing in breast carcinoma: very low concordance rate between reference and local laboratories in Brazil.

Breast cancer accounts for approximately one quarter of all cancers in females. HER2 gene amplification or HER2 protein overexpression, detected in about 20% of breast carcinomas, predicts a more aggressive clinical course and determines eligibility for targeted therapy with trastuzumab. HER2 testing has become an essential part of the clinical evaluation of all breast carcinoma patients, and accurate HER2 results are critical in identifying patients who may be benefited from targeted therapy. This study investigated the concordance in the results of HER2 immunohistochemistry assays performed in 500 invasive breast carcinomas between a reference laboratory and 149 local laboratories from all geographic regions of Brazil. Our results showed an overall poor concordance (171 of 500 cases, 34.2%) regarding HER2 results between local and reference laboratories, which may be related to the low-volume load of HER2 assays, inexperience with HER2 scoring system, and/or technical issues related to immunohistochemistry in local laboratories. Standardization of HER2 testing with rigorous quality control measures by local laboratories is highly recommended to avoid erroneous treatment of breast cancer patients.

Epithelioid angiosarcoma of the skin: a study of 18 cases with emphasis on its clinicopathologic spectrum and unusual morphologic features.

We report 18 cases of cutaneous angiosarcoma with predominant or exclusive epithelioid morphology. Both sexes were similarly affected. Patients' ages ranged from 2 to 97 years, median 77.5 years; 2 were pediatric patients. In elderly patients scalp or facial lesions and cutaneous lesions arising within irradiated breast skin predominated. Limb lesions were seen in younger patients. Microscopically, the tumors were composed of packed polygonal cells with focal evidence of endothelial differentiation. Diverging phenotypes included syncytial growth of large cells with clear nuclei and prominent nucleoli, micronodules of tumor cells scattered in dermis, predominance of discohesive plasmacytoid polygonal cells with abundant bright eosinophilic cytoplasm, sheets of clear cells with coarse granular cytoplasm, trabecular and cord arrangement of tumor cells splaying the dermal collagen, or a pseudoglandular appearance owing to clear cell tubular arrangement with open lumina. These cases posed further diagnostic challenges simulating lymphoma, melanoma, lymphoepithelioma-like carcinoma, adnexal carcinoma, and neuroendocrine carcinoma. Immunohistochemical studies showed positivity for CD31 and CD34; no immunoreactivity was documented for other tested antigens including cytokeratins, S100 protein, melanocytic antigens, leukocyte common antigen, and desmin. Therapeutic modalities included combined local excision, chemotherapy, and radiotherapy, depending on patient clinical status. Of the 9 patients available for follow-up, 5 were alive and apparently well, 2 had recurrent disease, and 2 had died of tumor. Our data show that epithelioid cutaneous angiosarcoma may have a broad morphological spectrum, raising interpretive challenges on microscopy. In addition, its clinical presentation seems to differ in nonelderly patients, with lesions likely related to lymphedema or vascular malformations.

Desmoplastic small round cell tumor of the kidney mimicking Wilms tumor: a case report and review of the literature.

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive, malignant neoplasm usually present with the widespread abdominal serosal involvement and affects mainly adolescents and young adults. When presenting within visceral organs, as kidney, the diagnosis of DSRCT imposes significant difficulties. We present a case of primary DSRCT of the kidney in a 10-year-old boy mimicking clinically and pathologically Wilms tumor. The tumor showed morphologic and immunohistochemical features of DSRCT and the presence of the Ewing sarcoma and Wilm tumor 1 fusion transcripts resulting from the t(11;22) (p13;q12) reciprocal translocation. DSRCT should be considered in the differential diagnosis of Wilm tumor and other small blue-round cell tumors of the kidney.