A great mimicker of primary biliary cholangitis

A 59 year-old man without past medical history was referred with biochemical features of cholestasis (aspartate aminotransferase (AST) 117 U/L, alanine aminotransferase (ALT) 83 U/L, gamma-glutamyl transferase (GGT) 1307 U/L, alkaline phosphatase (AP) 1803 U/L, total bilirubin 0,7 mg/dL), a strongly positive antimitochondrial M2 antibody (AMA-M2) titer (88 U), weight loss and abdominal pain since several months. He did not take any medications, nor there was a history of alcohol abuse or sexual risk behavior. Upon presentation, clinical examination showed a rather cachectic patient (body mass index 19 kg/m²), without further abnormalities. As primary biliary cholangitis (PBC) was suspected, treatment with ursodeoxycholic acid had been initiated but did not improve the cholestasis nor the pain. Additional investigations didn’t reveal any other irregularities, except for a mildly dilated aortic sinus root of 42 mm. The histopathological findings of a liver biopsy are shown below (Figure 1). This showed granulomas with cholangitis and increased presence of neutrophils, which raised suspicion for an infectious cause.

Dystrophic Adipocytes Mimicking Metastatic Signet Ring Cell Adenocarcinoma: A Diagnostic Pitfall in a Cachectic Patient

Cachexia is a debilitating condition and complex syndrome commonly associated with a variety of chronic diseases. It is caused by metabolic dysregulation and characterized by profound loss of adipose tissue and skeletal muscles. While pathological changes of cachectic conditions on adipose tissue have been studied and documented in tumor-bearing animal models, similar morphological changes in human surgical specimens are rare. Here we report a case of a cachectic patient with pancreatic adenocarcinoma whose adipocytes underwent dramatic lipodystrophy mimicking signet ring cell adenocarcinoma. The patient had presented with a large bowel obstruction, a mass extending between the pancreas and colon, and radiographic concern for carcinomatosis. A moderately differentiated adenocarcinoma was identified invading externally into the colon, with extensive signet ring-like cells throughout the specimen, including those adjacent to the colon and lymph nodes and around nerves. These signet ring-like cells were round with variably clear to eosinophilic cytoplasm and a peripherally displaced round to oval nucleus. Immunohistochemical staining demonstrated that these signet ring-like cells were negative for AE1/AE3, CD138, or Kreyberg staining, while they were positive for S-100 staining, confirming these as dystrophic adipocytes. Here we examine dystrophic adipocytes in a cachetic patient, examining the differential diagnosis and potential ancillary studies.