Severe Acute Pancreatitis Rapidly Developed Into Pulmonary Edema and Diffuse Alveolar Hemorrhage Leading to Respiratory Failure: An Autopsy Case.

Acute pancreatitis often results in life-threatening situations, making a prompt and accurate diagnosis cardinally important. To achieve these, it is crucial to correctly identify characteristic symptoms and test findings. However, when patients do not exhibit distinctive symptoms during a physician's examination, in addition to limited resources, these can become challenging. In this manuscript, we present an instructive case. A male in his twenties, who complained of generalized malaise, was admitted to our hospital. Unfortunately, however, he passed away within two days prior to undergoing detailed examinations or receiving therapeutic interventions. We performed an autopsy in order to ascertain the reasons for this outcome. The findings revealed that pulmonary edema and diffuse alveolar hemorrhage were the causative factors of his demise, with acute pancreatitis observed in the background. The occurrence of acute pancreatitis leading to death in youths is infrequent. Where could we have intervened to halt such an unfortunate course in a young individual? This patient probably had diabetic ketoacidosis and hyperlipidemia, both of which are known to be closely associated with acute pancreatitis. In retrospect, we should have noticed this point. In this case, the condition progressed too rapidly for appropriate therapeutic interventions. We believe that this case would provide educational instruction for similar situations that could arise in the future.

Ischemia-induced intestinal de-epithelization and consequent cholangitis lenta after usage of extracorporeal membrane oxygenation in COVID-19 patients: an autopsy series.

Since its discovery in late 2019, severe acute respiratory syndrome coronavirus 2 has spread around the world, causing millions of deaths due to coronavirus disease 2019 (COVID-19). Numerous clinical and post-mortem investigations of COVID-19 cases have found myriad clinical and pathological manifestations of the disease. In this report, we present three autopsy cases in which, despite weaning from extracorporeal membrane oxygenation (ECMO), extensive intestinal epithelial shedding, probably due to ischemia, was followed by massive watery diarrhea and the spread of infection via the portal vein due to bacterial translocation, which resulted in cholangitis lenta. Thrombophilia was attributed to ECMO usage and COVID-19-related vascular endothelial damage. These cases provide instructive findings showing that the loss of the intestinal barrier may be the underlying cause of severe watery diarrhea and liver failure in COVID-19 patients, especially with ECMO usage.

Metastatic pulmonary pleomorphic carcinoma replaced by a granulomatous lesion after spontaneous regression and PD-1 blockade-induced regression: can epithelioid granuloma be a histological hallmark of cancer immunity?

Immune checkpoint inhibitors (ICIs) for various types of malignancy, including non-small-cell lung cancer, have improved prognosis in some cases. Granuloma formation after ICI administration suggests a tumor antigen-specific cytotoxic T cell response with abundant interferon-gamma production, which can be used to estimate the curative effect of ICIs. In this report, we present a case with a resected lung lesion, clinically suspected to be lung cancer, that consisted of a granulomatous lesion. A tumor was also found in the duodenum that was presumed to be derived from the pulmonary pleomorphic carcinoma. Duodenal tumor cells highly expressed PD-L1, suggesting PD-1/PD-L1 axis-mediated immune escape. As expected, pembrolizumab induced a complete response for the duodenal lesion. Interestingly, in histopathological analysis, the duodenal lesion was also replaced by an epithelial granuloma and multinucleated giant cells. We conclude that autoimmunity regressed the untreated primary lung lesion spontaneously, while the metastatic duodenal lesion responded to PD-1 blockade. Tumor-associated epithelioid granulomas, even before ICI administration, may be an important pathological finding indicating an immune response with interferon-gamma production by cytotoxic T cells to the tumor.

Usefulness of SynCAM3 and cyclin D1 immunohistochemistry in distinguishing superficial CD34-positive fibroblastic tumor from its histological mimics.

Superficial CD34-positive fibroblastic tumor (SCPFT) is a fibroblastic/myofibroblastic soft tissue tumor of rarely metastasizing intermediate malignancy. Some recent studies have described a relationship between SCPFT and PRDM10-rearranged soft tissue tumor (PRT) based on SynCAM3 and PRDM10 expression on immunohistochemistry. We performed CD34, cytokeratin AE1/AE3, SynCAM3, and PRDM10 immunohistochemistry in SCPFT and its histological mimics, including myxoinflammatory fibroblastic sarcoma (MIFS), superficially localized myxofibrosarcoma (MFS), and undifferentiated pleomorphic sarcoma. We also examined cyclin D1 expression because it is expressed in MIFS and MFS. We conducted fluorescence in situ hybridization (FISH) of PRDM10 rearrangement in SCPFT cases. On immunohistochemistry, only SCPFT showed strong and diffuse SynCAM3 expression. SCPFT also exhibited strong nuclear and weak cytoplasmic cyclin D1 expression, which was similar to that observed in MIFS. Two of five SCPFT cases exhibited nuclear PRDM10 expression. FISH revealed PRDM10 split signals in 44% and 24% of tumor cells in two SCPFT cases showing nuclear PRDM10 expression on immunohistochemistry, respectively. A minority of non-SCPFT cases showed focal SynCAM3 expression, but a combination of SynCAM3 and cyclin D1 in addition to CD34 and cytokeratin AE1/AE3 may be useful for the differential diagnosis of SCPFT and its histological mimics.

Diagnostic utility of CSF1 immunohistochemistry in tenosynovial giant cell tumor for differentiating from giant cell-rich tumors and tumor-like lesions of bone and soft tissue.

BACKGROUND: Tenosynovial giant cell tumor (TSGCT) is a benign fibrohistiocytic tumor that affects the synovium of joints, bursa, and tendon sheaths and is categorized into localized TSGCT (LTSGCT) and diffuse TSGCT (DTSGCT). LTSGCT and DTSGCT are characterized by recurrent fusions involving the colony-stimulating factor 1 (CSF1) gene and its translocation partner collagen type VI alpha 3 chain. The fusion gene induces intratumoral overexpression of CSF1 mRNA and CSF1 protein. CSF1 expression is a characteristic finding of TSGCT and detection of CSF1 mRNA and CSF1 protein may be useful for the pathological diagnosis. Although there have been no effective anti-CSF1 antibodies to date, in situ hybridization (ISH) for CSF1 mRNA has been performed to detect CSF1 expression in TSGCT. We performed CSF1 immunohistochemistry (IHC) using anti-CSF1 antibody (clone 2D10) in cases of TSGCT, giant cell-rich tumor (GCRT), and GCRT-like lesion and verified its utility for the pathological diagnosis of TSGCT. METHODS: We performed CSF1 IHC in 110 cases including 44 LTSGCTs, 20 DTSGCTs, 1 malignant TSGCT (MTSGCT), 10 giant cell tumors of bone, 2 giant cell reparative granulomas, 3 aneurysmal bone cysts, 10 undifferentiated pleomorphic sarcomas, 10 leiomyosarcomas, and 10 myxofibrosarcomas. We performed fluorescence ISH (FISH) for CSF1 rearrangement to confirm CSF1 expression on IHC in TSGCTs. We considered the specimens to have CSF1 rearrangement if a split signal was observed in greater than 2% of the tumor cells. RESULTS: Overall, 50 of 65 TSGCT cases, including 35 of the 44 LTSGCTs and 15 of the 20 DTSGCTs, showed distinct scattered expression of CSF1 in the majority of mononuclear tumor cells. MTSGCT showed no CSF1 expression. Non-TSGCT cases were negative for CSF1. FISH revealed CSF1 rearrangement in 6 of 7 CSF1-positive cases on IHC. On the other hand, FISH detected no CSF1 rearrangement in all CSF1-negative cases on IHC. Thus, the results of IHC corresponded to those of FISH. CONCLUSION: We revealed characteristic CSF1 expression on IHC in cases of TSGCT, whereas the cases of non-TSGCT exhibited no CSF1 expression. CSF1 IHC may be useful for differentiating TSGCTs from histologically mimicking GCRTs and GCRT-like lesions.

COVID-19-associated disseminated mucormycosis: An autopsy case report.

BACKGROUND: Reports of mucormycosis, an infectious disease that commonly affects immunocompromised individuals, have increased during the ongoing coronavirus disease 2019 (COVID-19) pandemic. Disseminated mucormycosis associated with COVID-19 is rare but fatal and is characterized by an aggressive clinical course and delayed diagnosis. Our report documents a case of disseminated mucormycosis after COVID-19 infection. This is a rare pathological autopsy report on COVID-19-associated mucormycosis. CASE SUMMARY: A 58-year-old man was transferred to our hospital with severe COVID-19 pneumonia. During treatment for acute respiratory distress syndrome, he developed intra-abdominal bleeding that required a right hemicolectomy and ileostomy for hemostasis. The ileostoma and surgical wound developed necrosis followed by sepsis and multi-organ failure, which led to death. An autopsy revealed multiple thrombi associated with Rhizopus oryzae infection, which led to the necrosis of multiple infected organs. CONCLUSION: Early suspicion and diagnosis followed by treatment are keys to better outcomes of mucormycosis in patients with severe COVID-19.

Atypical spindle cell/pleomorphic lipomatous tumor with a sarcomatous component showing high mitotic activity and Ki-67 labeling index: report of a unique case mimicking dedifferentiated liposarcoma.

Atypical spindle cell/pleomorphic lipomatous tumor (ASPLT) is a new entity of benign adipocytic tumor that spans a wide spectrum of histology from adipocytic to spindle cell/pleomorphic tumors. The latter non-adipocytic component rarely shows sarcomatous features although ASPLTs are not thought to dedifferentiate. A 78-year-old woman with ASPLT in the left thigh had a sarcomatous component with high mitotic activity and Ki-67 labeling index (LI) mimicking dedifferentiated liposarcoma. The adipocytic component consisted of various-sized adipocytic cells with few lipoblasts. The sarcomatous component consisted of a fascicular proliferation of atypical spindle cells with scattered large bizarre and multinucleated giant cells. Mitotic figures including atypical mitoses were frequently observed. Immunohistochemically, the tumor cells were positive for cluster of differentiation 34 but not mouse double minute 2 homolog (MDM2), cyclin-dependent kinase 4 (CDK4), or retinoblastoma (Rb) protein. Ki-67 LI in the sarcomatous component reached 40%. MDM2 and CDK4 genes were not amplified and 13q14 including the RB1 locus was deleted according to fluorescence in situ hybridization. The patient is alive with no evidence of local recurrence or distant metastasis 3.5 years after surgery. As ASPLT may exhibit morphological variation, it is important to rule out dedifferentiated liposarcoma with careful pathological examination.