A 39-year-old female presented with a fleshy nasal polyp occluding the left nasal cavity, associated with haemopurulent discharge. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans of the paranasal cavities revealed a large polypoid tumour arising from the left middle turbinate and obstructing the left maxillary sinus ostium. However, no bony or intracranial involvement was identified. A biopsy revealed a tumour with small blue round cell morphology. The tumour cells showed diffuse strong membranous CD99 positivity and patchy CD34 positivity. Ancillary cytogenetic tests for the EWSR1 and SS18/SYT gene translocations were negative. In view of the non-invasive nature of the tumour and the low cell proliferative index (Ki-67) of 5%, a medial maxillectomy resection was performed. The resection revealed additional areas with spindle-cell morphology and focal haemangiopericytic vasculature. The tumour continued to show immunoreactivity to CD99 and CD34, as well as Smooth Muscle Actin (SMA) and Muscle Specific Actin (MSA). The overall findings are in keeping with a sinonasal haemangiopericytoma. With clear surgical resection margins, the patient is on routine follow-up and is currently disease-free.

A 50-year-old male of Indian descent presented with jaundice and right hypochondrium pain. Following a computed tomography (CT) scan of the abdomen, a segment 7 liver lesion was visualized, accompanied by extensive peritoneal tumour deposits. An ultrasound guided liver biopsy was performed and histology showed loose nests and sheets of tumour cells with a small blue round cell morphology. The tumour cells showed patchy strong immunopositivity for cytokeratins (AE1/3, CK7, CK19) and synaptophysin, while showing diffuse strong perinuclear positivity for desmin. Interphase fluorescence in-situ hybridization (FISH) study using EWSR1 breakapart probe was positive for EWSR1 gene rearrangement. Desmoplastic small round cell tumour is a rare but aggressive intra-abdominal mesenchymal tumour. While the primary sites of involvement are usually the peritoneum and omentum, visceral involvement can occur. We wish to highlight the importance of considering this entity when evaluating a liver biopsy especially in a less than classical clinical context.

A 20-year-old male presented with persistent right testicular pain. Following ultrasound detection of testicular nodules and biopsy for intraoperative consultation which yielded germ cell tumour, he underwent radical orchidectomy. A predominantly whitish cyst and a lobulated, variegated nodule were identified. Histology showed a mature cystic teratoma with a focus of infiltrative epithelioid cells containing eosinophilic cytoplasm and pleomorphic nuclei, invading ectatic vessel wall associated with fibrinoid change. These cells were positive for cytokeratin, human placental lactogen and inhibin, while negative for Melan-A, p63 and alpha-fetoprotein, consistent with placental site trophoblastic tumor (PSTT). The variegated nodule was a mixed germ cell tumour composed of embryonal carcinoma and immature teratoma. Aside from choriocarcinoma, primary trophoblastic tumors such as PSTT, which are derived from intermediate trophoblasts, are extremely rare in the testis. Aside from a case of pure testicular PSTT, 2 other cases have been described in association with germ cell tumour, of which one is a mature teratoma with PSTT that demonstrated gain of chromosome 12p. The other presented with PSTT in retroperitoneal recurrence of a testicular mixed germ cell tumour. We discussed the features of this tumour in the testis and important differentials in its diagnosis.

Hepatic tuberculosis (HTB) is an uncommon manifestation of tuberculous infections, and there has been no proven causal link between HTB and hepatocellular carcinoma (HCC). We herein present a rare case of a synchronous presentation of HTB and HCC within a single hepatic mass. A 57-year-old Chinese gentleman with recently diagnosed sigmoid adenocarcinoma was found to have a left lower lobe pulmonary nodule and solitary hepatic mass on staging computed tomography. Biopsies showed the hepatic mass to have both HTB and HCC components. This serves as a reminder that HTB is an important differential to consider for space-occupying lesions in the liver. Histological evaluation of suspected hepatic malignancies is recommended to exclude the presence of HTB in appropriate clinical settings.

Gastrointestinal stromal tumour (GIST) is a common mesenchymal tumour arising in the gastrointestinaltract, but not frequently encountered in the rectum. Herein, we describe a case of a rectal GISTwhich mimicked histomorphological features of a schwannoma; thus, making intraoperative frozensection evaluation challenging. Although subsequent immunohistochemistry and molecular findingsreadily confirmed the diagnosis of a GIST, we wish to draw attention to three clues that will help thepathologist steer clear of this potential diagnostic pitfall. One, GISTs are relatively more commonthan schwannomas in the rectum. Two, schwannomas usually have very little mitoses. Three,rectal GISTs commonly exhibit nuclear palisades. We also discuss the diagnostic, prognostic andtherapeutic functions of immunohistochemical and molecular investigations. As the surgical intentfor rectal GISTs is for en-bloc excision with wide margins, we surmise that the intraoperative consultshould include GIST as a possible differential diagnosis for rectal mesenchymal tumours. In view ofthe potential for neoadjuvant treatment with imatinib before surgical excision to preserve sphincterfunction, a multidisciplinary approach is recommended for establishing most effective treatmentstrategy in these rare complex cases.

Hepatic Epstein-Barr virus–positive inflammatory follicular dendritic cell sarcoma (EBV+ IFDCS) represents a rare form of liver malignancy. The absence of distinct clinical and radiological characteristics, compounded by its rare occurrence, contributes to a challenging diagnosis. Here, we report a case of a 54-year-old Chinese female with a background of chronic hepatitis B virus treated with entecavir and complicated by advanced fibrosis presenting with a liver mass found on her annual surveillance ultrasound. Hepatectomy was performed under clinical suspicion of hepatocellular carcinoma. Immunomorphologic characteristics of the tumor were consistent with EBV+ IFDCS with distinct non-caseating granulomatous inflammation. Our case illustrates the importance of considering EBV+ IFDCS in the differential diagnosis of hepatic inflammatory lesions. Awareness of this entity and its characteristic features is essential for accurately diagnosing and managing this rare neoplasm.

Hepatic Epstein-Barr virus–positive inflammatory follicular dendritic cell sarcoma (EBV+ IFDCS) represents a rare form of liver malignancy. The absence of distinct clinical and radiological characteristics, compounded by its rare occurrence, contributes to a challenging diagnosis. Here, we report a case of a 54-year-old Chinese female with a background of chronic hepatitis B virus treated with entecavir and complicated by advanced fibrosis presenting with a liver mass found on her annual surveillance ultrasound. Hepatectomy was performed under clinical suspicion of hepatocellular carcinoma. Immunomorphologic characteristics of the tumor were consistent with EBV+ IFDCS with distinct non-caseating granulomatous inflammation. Our case illustrates the importance of considering EBV+ IFDCS in the differential diagnosis of hepatic inflammatory lesions. Awareness of this entity and its characteristic features is essential for accurately diagnosing and managing this rare neoplasm.

Hepatic Epstein-Barr virus–positive inflammatory follicular dendritic cell sarcoma (EBV+ IFDCS) represents a rare form of liver malignancy. The absence of distinct clinical and radiological characteristics, compounded by its rare occurrence, contributes to a challenging diagnosis. Here, we report a case of a 54-year-old Chinese female with a background of chronic hepatitis B virus treated with entecavir and complicated by advanced fibrosis presenting with a liver mass found on her annual surveillance ultrasound. Hepatectomy was performed under clinical suspicion of hepatocellular carcinoma. Immunomorphologic characteristics of the tumor were consistent with EBV+ IFDCS with distinct non-caseating granulomatous inflammation. Our case illustrates the importance of considering EBV+ IFDCS in the differential diagnosis of hepatic inflammatory lesions. Awareness of this entity and its characteristic features is essential for accurately diagnosing and managing this rare neoplasm.

Cell Proliferation ; Cytoplasm ; metabolism ; Female ; Giant Cells ; pathology ; Humans ; Hysterectomy ; Immunophenotyping ; Middle Aged ; Perivascular Epithelioid Cell Neoplasms ; diagnosis ; Salpingectomy ; Uterine Neoplasms ; diagnosis

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of diseases characterized by fatty accumulation in hepatocytes, ranging from steatosis, non-alcoholic steatohepatitis, to cirrhosis. While histopathological evaluation of liver biopsies plays a central role in the diagnosis of NAFLD, limitations such as the problem of interobserver variability still exist and active research is underway to improve the diagnostic utility of liver biopsies. In this article, we provide a comprehensive overview of the histopathological features of NAFLD, the current grading and staging systems, and discuss the present and future roles of liver biopsies in the diagnosis and prognostication of NAFLD.