Immunohistochemistry in the workup of prostate biopsies: Frequency, variation and appropriateness of use among pathologists practicing at an academic center.

OBJECTIVES: We studied the frequency, inter-pathologist variation, appropriateness and utility of immunohistochemistry (IHC) performed on prostate biopsies (PB) to determine the significance of foci of suspicious glands/atypical small acinar proliferations (ASAP). METHODS: We calculated the rate of IHC use and diagnostic rate of ASAP and adenocarcinoma in PB from 01/01/2008 to 06/30/2015 for individual pathologists working in a tertiary academic institution, and correlated them with the pathologists' experience, subspecialization and PB volume with the aim of determining the interpathologist variation and appropriateness of use of IHC according to recently published recommendations, and the usefulness of IHC to resolve foci of ASAP as either benign or adenocarcinoma. RESULTS: IHC was used in 966/2652 (36.4%, 95% CI 33.4-39.4%) PB cases and 1915 of 16,359 (11.7%, 95% CI 11.2%-12.2%) of PB blocks and allowed definitive diagnosis of either benign or malignant in 75.8% (95% CI 73.9-77.7%) of blocks. By pathologist, IHC use rates varied more than twofold (22.8-50.5%); higher use was found for pathologists with genitourinary pathology specialization, higher PB volume and more experience, and correlated with higher rates of both ASAP and adenocarcinoma diagnoses. The use of IHC stains was considered appropriate in 822/966 (85.1%, 95% CI 82.9-87.4%) cases. CONCLUSIONS: Despite the fact that the use of IHC stains was considered useful and deemed appropriate in the majority of cases, it showed wide variation between pathologists, suggesting monitoring of IHC use rates may be useful to standardize its use.

Subglottic Basal Cell Adenocarcinoma.

OBJECTIVES: To discuss the presentation and management of a rare neoplasm in a previously unreported laryngeal subsite. METHODS: Case report and literature review. RESULTS: An 89-year-old woman presented with a subglottic mass, biopsy of which was consistent with basal cell adenocarcinoma. She was successfully treated with surgical intervention and remains disease free 29 months postoperatively. CONCLUSIONS: Basal cell adenocarcinoma is a rare salivary gland tumor, the laryngeal variant of which is even scarcer. Herein we describe the presentation and successful surgical management of the first reported case of subglottic basal cell adenocarcinoma. We additionally provide a histologic review followed by approaches to treatment.

Defining thyroid spherules: A benign cytomorphologic feature that mimics microfollicles.

BACKGROUND: Distinctive rounded structures termed spherules have been observed in thyroid fine-needle aspiration (FNA) samples. Although they are often small and interpreted as microfollicles, spherules are notable for the even spacing of the follicular cells along the perimeter of the structure. Because they have an orderly architectural arrangement, it has been hypothesized that spherules are benign and do not carry the same risk of malignancy that traditional microfollicles do. The aim of this study was to identify the clinical significance and histopathologic correlate of spherules. METHODS: Thyroid FNAs (n = 637) with an interpretation of atypia of undetermined significance (AUS) were reviewed for the presence of spherules, which were defined as small follicles with a rounded, smooth, sharply defined outer contour, evenly spaced nuclei, and a 3-dimensional appearance. Cases were included if spherules accounted for >50% of follicular cell arrangements. Clinical, histopathologic, molecular, and sonographic follow-up data were obtained. RESULTS: Twenty-five spherule cases were identified, and they represented 3.9% of all AUS cases reviewed. All 24 cases with follow-up had a benign outcome. Eleven were tested with the Afirma gene expression classifier; 8 were benign according to the gene expression classifier, and 3 were suspicious but histologically benign after surgical resection. Four additional cases were histologically benign after surgery. Five patients had repeat benign cytology. Four patients had repeat stable ultrasound findings. CONCLUSIONS: Thyroid nodules diagnosed as AUS, if composed predominantly of spherules, are associated with a benign outcome. Recognizing this distinctive cytomorphologic finding may help to reduce the number of FNAs interpreted as AUS and save patients from unnecessary additional testing and surgery.

Metastatic Renal Cell Carcinoma as Solitary Subcentimeter Polypoid Gastric Mucosal Lesions: Clinicopathologic Analysis of Five Cases.

BACKGROUND: The stomach is an uncommon site for metastatic carcinoma. Approximately 6% of renal cell carcinomas (RCCs) may metastasize to the stomach. The majority of the reported metastatic RCCs in the stomach presented as large masses or ulcers greater than a centimeter in size. It is very rare to encounter metastatic RCC as a solitary small polypoid gastric mucosal lesion. METHODS: In this study, we collected surgical pathology cases of gastric metastasis from RCC that measured 1.0 cm or less at the time of endoscopy. The clinicopathological characteristics were analyzed. RESULTS: Five patients with subcentimeter metastatic RCC involving the gastric mucosa were identified. The clinical presentation for upper endoscopic examination was non-specific. Two of the five patients did not have a known history of RCC. In the three patients with a previous history of RCC, the interval from primary RCC diagnosis to the detection of gastric mucosal metastasis was 5, 6, and 10 years, respectively. Endoscopically, all the lesions were solitary, ranging in size from 0.4 to 1 cm. Histologically, all five cases were of the clear cell type consisting of a bland clear cell proliferation within the lamina propria. Although the tumor cells were relatively bland, the presence of clear cytoplasm, nuclear membrane irregularity, occasional enlarged hyperchromatic atypical nuclei, and destructive growth in the center of the lesion should promote immunohistochemical workup. Immunohistochemically, the RCC cells exhibited at least patchy immunoreactivity for cytokeratin and RCC markers. In two cases, there were many CD68 positive foamy histiocytes intermingled with the tumor cells. CONCLUSION: Metastatic RCC can rarely present as subcentimeter polypoid gastric mucosal lesions. The remote or unknown history of RCC, the non-specific endoscopic appearance, and the bland histological features may lead to a potential diagnostic pitfall. It is of importance to raise the awareness of such an unusual presentation of metastatic RCC in the stomach and to include metastatic RCC in the differential diagnosis for gastric mucosal polyps with clear cell morphology.