Effect of ischemic time, fixation time, and fixative type on HER2/neu immunohistochemical and fluorescence in situ hybridization results in breast cancer.

Accurate determination of HER2/neu status in breast carcinoma is essential. Alteration of preanalytic variables is known to affect HER2/neu results. American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) issued guidelines to standardize fixation for increased HER2/neu accuracy. We studied the effects of changing preanalytic variables on HER2/neu immunohistochemical and fluorescence in situ hybridization (FISH) results in a known HER2/neu+ invasive carcinoma. The clinical specimen was processed according to ASCO/CAP guidelines, with remaining tumor stored fresh without any fixatives for 4 days at 4°C and cut into core biopsy-sized pieces. Each was fixed in 10% formalin, 15% formalin, Pen-Fix (Richard-Allan Scientific, Kalamazoo, MI), Bouin solution, Sakura molecular fixative (Sakura Tissue-Tek Xpress, Torrance, CA), or zinc formalin for 0 to 168 hours. Immunohistochemical studies and FISH were performed. Compared with the clinical specimen, the samples showed no tumor degradation or marked difference by immunohistochemical studies, except the 1-hour 10% formalin and Bouin samples, or FISH, except the Bouin-fixed samples. Our study demonstrates that HER2/neu results remain accurate beyond ASCO/CAP-recommended preanalytic variables, with the exception of Bouin solution for FISH analysis.

The effect of delay in fixation, different fixatives, and duration of fixation in estrogen and progesterone receptor results in breast carcinoma.

Accurate determination of estrogen receptor (ER) and progesterone receptor (PR) status in breast carcinoma is essential. Preanalytic variation may contribute to discordant results. Recently, American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) made recommendations to normalize fixation for breast biomarkers. To evaluate this, a 4-cm invasive lobular carcinoma was processed according to ASCO/CAP guidelines. The remainder was stored fresh at 4°C for 4 days and cut into biopsy-sized pieces. Each was fixed in 10% formalin, Pen-Fix (Richard-Allan Scientific, Kalamazoo, MI), Bouin solution, Sakura Molecular Fixative (Sakura Tissue-Tek Xpress, Torrance, CA), zinc formalin, or 15% formaldehyde for times ranging between 1 and 168 hours. Immunohistochemical studies for ER and PR were performed and interpreted. After 4 days at 4°C, all samples showed no degradation or ER/PR staining differences, except 2 Bouin-fixed samples, in comparison with the patient's sample processed according to ASCO/CAP guidelines. In our study, the preanalytic variables of fixative type, fixation time, and 4 days of ischemic time did not affect immunohistochemical accuracy for ER/PR.

Cutaneous carcinosarcoma with myoepithelial differentiation: immunohistochemical and cytogenetic analysis of a case presenting in an unusual location.

Primary cutaneous carcinosarcoma is an uncommon tumor that is characterized by an admixture of malignant epithelial and mesenchymal elements. To our knowledge, only approximately forty cases have been reported to date in the literature. The majority of these neoplasms occurred on the extremities and the head and neck region of older individuals. We report an additional case, which presented in an 87-year-old man in an unusual location, the buttock. Histologically, the lesion was characterized by a biphasic proliferation of malignant epithelial areas admixed with an infiltrative, poorly differentiated spindle cell component. The epithelial areas consisted of nodular aggregates of basaloid to squamoid cells forming focal ductal structures with central lumens containing proteinaceous debris. The sarcomatoid component consisted of malignant spindle to epithelioid-appearing cells admixed with bizarre-appearing tumor giant cells within a myxochondroid stroma. The epithelial cells showed positive staining with pan-cytokeratin, BerEP4, p63, and keratin 5/6 and were focally positive for S-100, calponin, and actin, consistent with myoepithelial differentiation. An epithelial membrane antigen stain highlighted the scattered ductal structures. The high-grade spindle cell areas were negative for S-100, actin, desmin, calponin, p63, epithelial membrane antigen, and keratin 5/6.

Renal cell carcinoma metastatic to Hurthle cell adenoma of thyroid.

Metastases to the thyroid gland are a common finding at autopsy in patients who died of malignancy and are often misdiagnosed as primary thyroid neoplasms clinically. We present a patient with a rare, unusual case of renal cell carcinoma (RCC) metastatic to a Hurthle cell adenoma of the thyroid. A 53-year-old woman was admitted to a University of Texas Medical Branch Hospital (Galveston, TX) for a large right thyroid mass that was present for 3 months. A fine needle aspiration of the thyroid mass was performed and interpreted as suggestive of a Hurthle cell neoplasm. A total thyroidectomy revealed Hurthle cell adenoma containing clusters of cytologically atypical cells with clear cytoplasm. Subsequent patient evaluation and computed tomography revealed a renal mass. Left radical nephrectomy was performed at a later date for left renal mass and the microscopic examination confirmed the diagnosis of primary clear cell carcinoma of the kidney. Further studies confirmed that the thyroid mass was metastases from RCC. Although carcinoma of the kidney is responsible in most instances of metastatic disease to the thyroid, metastatic RCC to a thyroid neoplasm is extremely rare, with only two reports found in the English literature. The possibility of metastatic RCC should always be taken under consideration, especially when nests of clear cells are seen infiltrating into the thyroid parenchyma or neoplasm.