Sofie Verbeke

Whipple’s disease in granulomatous disguise: a challenging diagnosis with many histopathological pitfalls

Whipple’s disease is a rare systemic illness caused by Tropheryma whipplei, a Gram-positive bacterium. Despite its abundant natural prevalence and reports on frequent asymptomatic carriage of T. whipplei, Whipple’s disease has an estimated annual incidence between only one and six per 10 million populations. This disease predominantly affects middle-aged white males [5, 6, 9]. Specific HLA constellations predispose to the development of Whipple’s disease by hampering the protective immune response that occurs in most infected individuals [5]. Impaired function of intestinal macrophages prevents the degradation of T. whipplei and results in massive accumulation of macrophages, laden with this intracellular pathogen, in the lamina propria of the small intestine [6]. Early reports on Whipple’s disease describe a Bclassic^ form, characterized by gastrointestinal symptoms such as diarrhea, malabsorption, abdominal pain, and weight loss [10]. Occasional case reports in the past decades have broadened our view on the clinical presentation, since they showed that Whipple’s disease can mimic many other conditions. Therefore, diagnosis is often delayed [1, 3, 8, 12]. Here, we describe an atypical presentation of Whipple’s disease, concerning a man who initially presented with cervical lymphadenopathy only. At first, he was misdiagnosed with sarcoidosis, a mimic of Whipple’s disease. Several biopsies were performed during the diagnostic process. Here, we discuss potential diagnostic pitfalls based on the obtained histopathological images.

Some diffuse large B-cell lymphomas (DLBCLs) present with clone-dependent TTF-1 positivity.

Sir: Thyroid-specific transcription factor 1 (TTF-1) is a transcription factor encoded by the NK2 homeobox 1 (NKX2-1) gene, located on chromosome 14. Because of its restricted expression pattern, TTF-1 used to be regarded as a specific marker for tumours originating in the thyroid and the lung, thereby facilitating investigations of cancers of unknown primary (CUPs). Immunohistochemistry for TTF-1 can differentiate primary pulmonary adenocarcinomas from lung metastases of non-pulmonary adenocarcinomas, and can distinguish solid pulmonary adenocarcinomas from squamous cell carcinomas of the lung. Increasing evidence indicates that TTF-1 expression can also occur in adenocarcinomas of non-pulmonary origin, such as the colon, prostate, endometrium, cervix and breast. This phenomenon constitutes a diagnostic challenge, as it might result in misdiagnosis of (metastatic) primary pulmonary adenocarcinoma. We recently encountered TTF-1 expression in a poorly differentiated neoplasm of uncertain origin, located subcutaneously on the thorax of a man with a history of pulmonary adenocarcinoma. Haematoxylin and eosin staining showed a poorly differentiated discohesive large cell neoplasm with pleomorphic vesicular nuclei and numerous mitotic figures. Glandular or squamous differentiation were lacking. Initial immunohistochemistry included markers for S100, TTF1 (SPT24 clone), broad-spectrum cytokeratin (AE1/AE3) and CD45 (Figure 1). The neoplasm was negative for S100 and cytokeratins, ruling out metastatic melanoma and carcinoma, respectively. Despite diffuse positive staining for

Dichotomous histopathological assessment of ductal carcinoma in situ of the breast results in substantial interobserver concordance

Robust prognostic markers for ductal carcinoma in situ (DCIS) of the breast require high reproducibility and thus low interobserver variability. The aim of this study was to compare interobserver variability among 13 pathologists, in order to enable the identification of robust histopathological characteristics.

Routine histopathological examination after female-to-male gender-confirming mastectomy: Routine histopathological examination after gender-confirming mastectomy

The number of transmen seeking gender‐confirming surgery has risen steadily throughout the last decade. Pathologists are increasingly confronted with transmale mastectomy specimens. It is not clear whether routine histopathological examination is useful. This study explored the possible benefit of routine investigation through detailed description of lesions encountered in mastectomy specimens after female‐to‐male gender‐confirming surgery.