Whole Slide Imaging Versus Microscopy for Primary Diagnosis in Surgical Pathology: A Multicenter Blinded Randomized Noninferiority Study of 1992 Cases (Pivotal Study).

Most prior studies of primary diagnosis in surgical pathology using whole slide imaging (WSI) versus microscopy have focused on specific organ systems or included relatively few cases. The objective of this study was to demonstrate that WSI is noninferior to microscopy for primary diagnosis in surgical pathology. A blinded randomized noninferiority study was conducted across the entire range of surgical pathology cases (biopsies and resections, including hematoxylin and eosin, immunohistochemistry, and special stains) from 4 institutions using the original sign-out diagnosis (baseline diagnosis) as the reference standard. Cases were scanned, converted to WSI and randomized. Sixteen pathologists interpreted cases by microscopy or WSI, followed by a wash-out period of ≥4 weeks, after which cases were read by the same observers using the other modality. Major discordances were identified by an adjudication panel, and the differences between major discordance rates for both microscopy (against the reference standard) and WSI (against the reference standard) were calculated. A total of 1992 cases were included, resulting in 15,925 reads. The major discordance rate with the reference standard diagnosis was 4.9% for WSI and 4.6% for microscopy. The difference between major discordance rates for microscopy and WSI was 0.4% (95% confidence interval, -0.30% to 1.01%). The difference in major discordance rates for WSI and microscopy was highest in endocrine pathology (1.8%), neoplastic kidney pathology (1.5%), urinary bladder pathology (1.3%), and gynecologic pathology (1.2%). Detailed analysis of these cases revealed no instances where interpretation by WSI was consistently inaccurate compared with microscopy for multiple observers. We conclude that WSI is noninferior to microscopy for primary diagnosis in surgical pathology, including biopsies and resections stained with hematoxylin and eosin, immunohistochemistry and special stains. This conclusion is valid across a wide variety of organ systems and specimen types.

The immunohistochemical profile of atypical eosinophilic syncytial changes vs serous carcinoma.

Endometrial epithelial cytoplasmic change (EECC) is an adaptive cytoplasmic change commonly seen in the endometrium. Previously considered "metaplasia," EECC is now the preferred term because it offers a descriptive designation without implying a specific mechanism of development. There are 5 types of EECC: squamous, ciliated cell, eosinophilic, mucinous, and secretory (clear cell and hobmail cell) changes. Eosinophilic syncytial change (ESC) is a similar but unrelated degenerative change seen in endometrial breakdown. Some cases of ESC show atypical cytologic features that may resemble endometrial adenocarcinoma. Thirteen endometrial biopsy and curettage specimens with atypical ESCs (AESCs) were compared against 10 hysterectomy specimens with endometrial serous carcinoma. Clinical information and immunohistochemical staining profiles for markers phosphatase and tensin homologue deleted on chromosome 10 (PTEN), p53, and Ki-67 were evaluated in each case. All 13 cases of AESC (100%) showed moderate-to-strong staining for PTEN, whereas PTEN expression was absent in all endometrial serous carcinomas (P < .001). Seven cases of AESC (54%) showed focal, weak positivity for p53, whereas all cases of serous carcinoma (100%) showed strong staining (P < .001). The Ki-67 index was low (3%-15%) and found in only 3 cases in AESC (32%) but was high (60%-90%) in all cases of endometrial serous carcinoma (100%) (P < .001). Atypical ESC and serous carcinoma share several morphological features on hematoxylin and eosin-stained sections that may complicate accurate diagnosis. The PTEN, p53, and Ki-67 staining profile can effectively distinguish between AESC and malignancy in difficult cases, providing an invaluable tool for a challenging diagnostic dilemma.

Poorly differentiated gastroenteropancreatic neuroendocrine carcinoma associated with X-linked hyperimmunoglobulin M syndrome.

Gastroenteropancreatic neuroendocrine tumors are uncommon tumors representing 2% of all gastrointestinal tumors. We report a case of a 21-year-old man with X-linked hyperimmunoglobulin M (hyper-IgM) syndrome who presented with diarrhea and jaundice. An ultrasound and magnetic resonance imaging showed multiple variable-sized lesions in the liver and peripancreatic lymphadenopathy. The morphologic and immunohistochemical features of the biopsies from the liver and lymph node were consistent with poorly differentiated neuroendocrine carcinoma. Hyper-IgM syndrome is a rare primary immunodeficiency disease characterized by low serum IgG, IgA, and IgE levels with normal or elevated IgM levels. These patients are at a higher risk for developing malignancies, particularly adenocarcinoma of the gastrointestinal tract and lymphoma. A review of the literature of gastroenteropancreatic neuroendocrine tumors is presented with the discussion of a possible relationship of these tumors with immunodeficiency.