Primary signet ring neuroendocrine tumors of the liver are extremely rare tumors. Morphologically, they mimic signet ring cell adenocarcinomas; however, the absence of mucin by special stains and the expression of neuroendocrine markers help to diagnose these tumors. We herein report a case of a 47-year-old female who presented with multiple solid and cystic lesions in both liver lobes, which were initially suggested to be biliary cystadenocarcinoma on imaging. Liver biopsy of the lesion revealed the presence of a signet ring neoplasm with diffuse expression of synaptophysin and pan-cytokeratin. The case was subsequently diagnosed as a primary hepatic signet ring neuroendocrine tumor. The patient was offered 3 cycles of chemotherapy and is well preserved after 14 months of diagnosis. Although this is an extremely rare entity, its possibility should be considered in the differential diagnosis of neoplasms characterized by signet ring cell morphology.

Primary signet ring neuroendocrine tumors of the liver are extremely rare tumors. Morphologically, they mimic signet ring cell adenocarcinomas; however, the absence of mucin by special stains and the expression of neuroendocrine markers help to diagnose these tumors. We herein report a case of a 47-year-old female who presented with multiple solid and cystic lesions in both liver lobes, which were initially suggested to be biliary cystadenocarcinoma on imaging. Liver biopsy of the lesion revealed the presence of a signet ring neoplasm with diffuse expression of synaptophysin and pan-cytokeratin. The case was subsequently diagnosed as a primary hepatic signet ring neuroendocrine tumor. The patient was offered 3 cycles of chemotherapy and is well preserved after 14 months of diagnosis. Although this is an extremely rare entity, its possibility should be considered in the differential diagnosis of neoplasms characterized by signet ring cell morphology.

Basidiobolus ranarum is known to cause subcutaneous mycoses; however, rare cases of hepatic and gastrointestinal involvement by basidiobolomycosis have been reported. Hepatic basidiobolomycosis may be confused with a carcinoma on imaging, and histological examination and fungal culture can help distinguish between these two. We report a rare case of basidiobolomycosis in a 16-year-old male with liver and gastrointestinal involvement.

An undifferentiated carcinoma (UC) of the gall bladder behaves aggressively and has a grave prognosis. Small cell type undifferentiated carcinoma of the gall bladder is a rare variant. This paper reports a case of UC of gall bladder with PAS-positive diastase-resistant eosinophilic hyaline globules present as liver mass (on imaging) in a male patient. The microscopic findings of the liver and gall bladder after a right tri-segmentectomy showed an un-differentiated malignant neoplasm composed of cells with round to oval nuclei, prominent nucleoli, and scanty neoplasm. No definite cell pattern was identified with these neoplastic cells. A section from the gall bladder revealed a tumor arising from the lining epithelium and infiltrating through the muscularis. This tumor was infiltrating the adherent liver tissue directly and forming a mass of undifferentiated malignant cells. The focal area within the tumor mass showed the presence of PAS-positive, diastase-resistant, eosinophilic hyaline globules within the neoplastic cells. The immunohistochemistry test was diffusely positive for perinuclear anti-neutrophil cytoplasmic antibodies and negative for chromogranin, vimentin, Desmin, alpha-fetoprotein, leukocyte common antigen, CD34, and bcl2. When the clinical and radiological data are inconclusive, careful analysis of the histological and immunophenotypic features is needed to make the final diagnosis of UC of the gall bladder. The biological behavior and prognosis of this tumor remain unclear because of its rarity. Further studies will be needed to understand the characteristics of this deadly tumor and to establish an effective therapy for it.