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We report a distinct, primary testicular tumor with peritubular myoid cell differentiation. A 25-year-old man developed a well-circumscribed testicular tumor composed of cytologically bland spindled cells, which were strongly and diffusely positive for desmin, smooth muscle actin, muscle-specific actin, and smooth muscle myosin. In addition, S-100 was diffusely positive, and cytokeratin (CK5/6 and AE1/3) was focally positive. Calretinin, inhibin, and CD34 were all negative. This pattern of immunoreactivity was very similar to the normal adjacent peritubular myoid cells. Follow-up after radical orchiectomy showed benign behavior. We found reports of 6 similar intratesticular tumors demonstrating peritubular myoid cell-like differentiation and having favorable outcome. We believe that the myoid gonadal stromal tumor is a rare, yet distinct, testicular tumor separate from leiomyoma and deserves recognition., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Benign lymphoid hyperplasia (pseudolymphoma) has been reported in the skin, lungs, orbit, and gastrointestinal tract, but only rarely in soft tissues. These lesions mimic lymphoma both clinically and histologically. We describe a case of a pseudolymphoma of the deep soft tissues of the lower extremity. The lesion was composed of nonencapsulated lymphoid tissue with involvement of adjacent fat and connective tissues and multiple variably sized well-polarized germinal centers. Immunohistochemical staining, flow cytometry, chromogenic in situ hybridization for κ/λ light-chain restriction, and polymerase chain reaction for T- and B-cell gene rearrangements all revealed a polyclonal population of T and B cells, consistent with a benign reactive process. So far as we know, pseudolymphoma of the deep soft tissues has been described only once previously in the medical literature., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The risk for developing celiac disease is associated with the major histocompatibility complex class II human leukocyte antigen DQ2 and DQ8. We retrospectively reviewed the medical records of 127 consecutive cases of adult-onset celiac disease evaluated at a single United States center to determine the distribution of the associated human leukocyte antigen DQA1 and DQB1 alleles. The median patient age of diagnosis was 41 (range, 16-81) years. Ninety-five adults underwent human leukocyte antigen DQ typing. Eighty patients were DQ2 positive, 24 were DQ8 positive, and 11 were DQ2 and DQ8 positive. Four patients carried the uncommon, low-risk haplotype DQ2.2 (DQA1*02 and DQB1*02) without DQA1*05. Two patients did not carry human leukocyte antigen DQ2 or DQ8. All of the patients with atypical human leukocyte antigen DQ responded to a gluten-free diet. Although the majority of patients carry the human leukocyte antigen DQ2 or DQ8, gluten-dependent enteropathy periodically presents in adults with low-risk alleles., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Adult nesidioblastosis is an uncommon cause of hyperinsulinemic hypoglycemia characterized by diffuse islet hyperplasia with beta-cell hypertrophy and atypia. The cause of nesidioblastosis in adults is unclear but may be different from nesidioblastosis in infants. In contrast to infants, a focal form of adult nesidioblastosis (ie, "nesidioblastoma") has not been documented, although proposed. We report a 44-year-old man with symptomatic hypoglycemia and localized nesidioblastosis treated with surgical enucleation resulting in normalization of blood glucose. Postoperative euglycemia has persisted in this patient to date (4 months at the time of manuscript submission)., (Copyright 2010 Elsevier Inc. All rights reserved.)

Thyroid transcription factor (TTF)-1 expression in neuroendocrine tumors (NETs) has not been studied as widely as that in non-NETs, with the exception of small cell carcinomas, in which TTF-1 is highly sensitive but not specific for a primary lung tumor. The reported incidence of TTF-1 expression in pulmonary carcinoids has also been highly variable in the literature. To evaluate the expression of TTF-1 in NETs and potential value of TTF-1 in distinguishing pulmonary NETs from those of extrapulmonary origin, we performed an immunohistochemical study by using semiquantitative analysis on formalin-fixed, paraffin-embedded sections from 111 NETs, including 80 pulmonary (11 carcinoid tumorlets [TLs] or foci of neuroendocrine cell hyperplasia [NEH], 36 typical carcinoids [TCs], 17 atypical carcinoids [ACs], 16 large cell neuroendocrine carcinomas [LCNECs]), 13 thymic (3 TCs, 8 ACs, 2 LCNECs), 17 gastrointestinal or pancreatic (13 TCs, 4 ACs), and 1 ovarian (LCNEC). Pulmonary carcinoids were subdivided into those with central and those with peripheral location. TTF-1 positivity was seen exclusively in pulmonary NETs and was significantly higher in NEH or TLs (72.7%) than in TCs (27.8%), ACs (29.4%), and LCNECs (37.5%; P = 0.03). All extrapulmonary NETs were uniformly negative for TTF-1 staining. Interestingly, 12 of 14 TTF-1-positive pulmonary TCs and ACs had a peripheral location with spindle cell morphology, as did all cases of TL, a purported precursor of peripheral carcinoids. In conclusion, TTF-1 expression was 100% specific, though not so sensitive, for the lung primary in TCs and ACs and possibly also in LCNECs. Prevalent TTF-1 positivity in TLs and peripheral carcinoids suggest that they may be histogenetically distinct from the central carcinoids, which are typically composed of TTF-1-negative, more rounded cells.

Tumor proliferation is inversely associated with survival in patients with breast carcinoma. Although the proliferation marker Ki-67 antigen correlates with mitotic figure count (MFC) in breast carcinoma (number of mitotic figures per high-powered field), the more precise association of Ki-67 antigen expression with mitotic figure index (MFI) (number of mitotic figures per tumor cells) and histologic grade remains incompletely defined, especially when using the new "paraffin"-reactive monoclonal antibody MIBI to mark the Ki-67 antigen. To determine the association of Ki-67 antigen expression with mitotic figure content we immunostained 50 formalin-fixed, paraffin-embedded breast carcinomas with the MIB1 monoclonal antibody and correlated the results with MFC, MFI, and Scarff-Bloom-Richardson grade. The Ki-67 antigen-labeling index (K67LI) was the number of MIBI-positive cells/1,000 tumor cells, the MFI was the number of mitotic figures/1,000 tumor cells, and the MFC was the number of mitotic figures/10 high-powered fields. The K67LI correlated highly with the MFI (r = .76, P < .0001), MFC (r = .78, P < .0001), and Scarff-Bloom-Richardson grade (r = .73, P < .0001). In addition, analysis of variance showed that MFI was more precise than MFC in estimating K67LI and thus a more repeatable measure of tumor proliferation. Moreover, measurements made by MFI were as precise as those made by K67LI. Therefore, the correlation of K67LI with mitotic figure content was strong enough to suggest that a very carefully measured MFI provides an estimate of tumor growth fraction equivalent to the K67LI. However, which method is optimal for estimating tumor proliferation rate remains unclear.

Infiltrating lobular carcinoma (ILC) of the classic type is well recognized; less well appreciated is a group of variant forms of ILC, which includes solid, alveolar, mixed, apocrine, signet-ring, histiocytoid, and tubulolobular variants. In addition, Page et al (Diagnostic Histopathology of the Breast, Churchill Livingstone, 1987, pp 219-226) recently have emphasized the pleomorphic variant of ILC, which demonstrates the infiltrating pattern of classic ILC; however, the nuclei are more pleomorphic and have features that may overlap with those of infiltrating duct carcinoma. To determine whether pleomorphic ILC shows significant prognostic differences from classic ILC, we reviewed the clinical courses of 25 patients with classic ILC and compared them with 16 patients with pleomorphic ILC. The major determinant in placing ILC into the pleomorphic category was the presence of nuclei of nuclear grade 2 or 3. All classic ILCs had nuclei of grade 1 by the Scarff-Bloom-Richardson criteria. Survival to recurrence was significantly worse (P less than or equal to .05) for the patients with pleomorphic ILC at lengths of survival greater than 30 months. In addition, node-negative patients with pleomorphic ILC were four times more likely to experience recurrence than node-negative patients with classic ILC; those with positive nodes and pleomorphic histology were 30 times more likely to experience recurrence. Although there appeared to be a trend toward decreased overall length of survival for those patients with pleomorphic ILC when compared with patients with classic ILC, this difference was not statistically significant.

To develop histologic criteria that allow distinction of prolapsed from nonprolapsed intervertebral disk material, we reviewed the histologic features of curetted fibrocartilage from 100 consecutive patients having documented disk prolapse into the spinal canal and contrasted our findings to those in 40 intervertebral disks removed at autopsy from 20 patients without prolapse. Neovascularization, occurring at the edges of fibrocartilage fragments, was present in 50% of prolapsed disk specimens and in none of the control autopsy disks (p = 0.0004). Other histologic features sometimes used as evidence of degeneration and/or prolapse (i.e., fibrillation, chondrocyte "cloning," and granular change) were not helpful in distinguishing prolapsed from nonprolapsed control disks. Although this indicator was only 50% sensitive in our series, we propose that edge neovascularization of the fibrocartilage fragments is the only reliable histologic clue that intervertebral disk prolapse has occurred.