The American journal of surgical pathology
-
Am. J. Surg. Pathol. · Sep 2014
Diagnostic pitfalls of differentiating desmoplastic small round cell tumor (DSRCT) from Wilms tumor (WT): overlapping morphologic and immunohistochemical features.
Desmoplastic small round cell tumor (DSRCT) and blastemal-predominant Wilms tumor (WT) share overlapping histologic features, yet accurate distinction is critical because of differing prognosis and treatment. We encountered a neck mass in a young adult with a concomitant abdominal mass. The neck mass was initially concerning for DSRCT on the basis of the poorly differentiated morphology, desmoplastic stroma, and immunoreactivity for desmin and cytokeratin. ⋯ Moreover, we demonstrate coexpression of desmin and cytokeratin in both DSRCT (9 of 12) and WT blastema (11 of 22). Importantly, although dot-like desmin reactivity and coexpression of desmin and cytokeratin are historically associated with DSRCT, we demonstrate that these features can be seen in either DSRCT or blastemal-predominant WT. In these challenging cases, detection of an EWSR1-WT1 rearrangement and selective WT1 carboxy-terminus immunoreactivity (characteristic of DSRCT) or dual immunoreactivity for the WT1 amino-terminus and carboxy-terminus (characteristic of WT) remain the most discriminating diagnostic tools.
-
Am. J. Surg. Pathol. · Sep 2014
Comparative StudyMorphologic and molecular characterization of traditional serrated adenomas of the distal colon and rectum.
Of the serrated polyps, the origin, morphologic features, molecular alterations, and natural history of traditional serrated adenomas (TSAs) are the least understood. Recent studies suggest that these polyps may arise from precursor lesions. The frequencies of KRAS and BRAF mutations vary between these studies, and only 1 small study has measured CpG island methylation using current markers of methylation. ⋯ Unlike sessile serrated adenomas/polyps, TSAs rarely had diffuse expression of ANXA10. Importantly, BRAF-mutated TSAs had more widespread methylation of a 5-marker CpG island panel compared with KRAS-mutated polyps. However, ectopic crypt foci, a proposed defining feature of TSA, were not associated with any specific molecular alteration.
-
Am. J. Surg. Pathol. · Apr 2014
Prognostic significance of adenocarcinoma in situ, minimally invasive adenocarcinoma, and nonmucinous lepidic predominant invasive adenocarcinoma of the lung in patients with stage I disease.
According to the IASLC/ATS/ERS classification, the lepidic predominant pattern consists of 3 subtypes: adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and nonmucinous lepidic predominant invasive adenocarcinoma. We reviewed tumor slides from 1038 patients with stage I lung adenocarcinoma, recording the percentage of each histologic pattern and measuring the invasive tumor size. Tumors were classified according to the IASLC/ATS/ERS classification: 2 were AIS, 34 MIA, and 103 lepidic predominant invasive. ⋯ CIR was lower for patients with ≤2 cm tumors than for those with >2 to 3 cm tumors (for both total and invasive tumor size), with the difference more pronounced for invasive tumor size (5-y CIR, 13% vs. 21% [total size; P=0.022] and 12% vs. 27% [invasive size; P<0.001]). Most patients with lepidic predominant adenocarcinoma who experienced a recurrence had potential risk factors, including sublobar resection with close margins (≤0.5 cm; n=2), 20% to 30% micropapillary component (n=2), and lymphatic or vascular invasion (n=2). It therefore may be possible to identify lepidic predominant adenocarcinomas that carry a low or high risk for recurrence.
-
Am. J. Surg. Pathol. · Apr 2014
BRAF V600E expression in Langerhans cell histiocytosis: clinical and immunohistochemical study on 25 pulmonary and 54 extrapulmonary cases.
Pulmonary Langerhans cell histiocytosis (PLCH) has been postulated to be a smoking-related non-neoplastic condition, distinct from extrapulmonary LCH, which is generally regarded as a clonal, neoplastic process. Recent genomic studies demonstrated BRAF V600E mutation in 38% to 57% of extrapulmonary LCH cases by polymerase chain reaction. We evaluated the BRAF V600E expression by immunohistochemistry (IHC) in PLCH and extrapulmonary LCH cases. ⋯ The cumulative tobacco exposure at the time of diagnosis was significantly higher in BRAF V600E-positive than in BRAF V600E-negative PLCH patients (mean pack-years 48.3 vs. 23.7, 2-tailed t test P=0.01). BRAF V600E expression by IHC correlated with BRAF V600E mutational status in most of the cases in our study except in 3 patients (4.4%). In conclusion, a subset of PLCH with BRAF V600E expression may be a clonal proliferative process, in which cigarette smoking might play a role.
-
Am. J. Surg. Pathol. · Mar 2014
Coexistent pulmonary granulomatosis with polyangiitis (Wegener granulomatosis) and Crohn disease.
Crohn disease (CD) may be associated with various extraintestinal manifestations, including, rarely, respiratory tract involvement. When necrobiotic pulmonary nodules are present, the differential diagnosis includes granulomatosis with polyangiitis (Wegener granulomatosis) (GPA). The respiratory tract manifestations of CD and GPA may mimic each other, complicating the diagnosis and suggesting the possible coexistence of these 2 conditions. ⋯ Myeloperoxidase-ANCA was negative in 6 cases and unavailable in the remainder of patients. Pathology revealed features diagnostic of GPA in all cases with necrotizing granulomatous inflammation and segmental vasculitis. Pulmonary findings in patients with CD or the presence of granulomatous colitis in patients with GPA should prompt the inclusion in the differential diagnosis of a possible coexistence of CD and GPA.