Pancreatic lymphoepithelial cyst with concurrent HIV infection: A case report and review of the literature.

Pancreatic lymphoepithelial cysts are rare, benign, non-neoplastic unilocular or multilocular cystic lesions. These circumscribed pancreatic lesions are filled with keratinous material grossly and exhibit distinct microscopic features. Pancreatic lymphoepithelial cysts are like the more common lymphoepithelial cysts of the parotid glands, which have been associated with the diffuse infiltrative lymphocytosis syndrome often seen in patients with HIV infection. However, pancreatic lymphoepithelial cysts are rare and their association with HIV infection has not been established. The presence of secondary changes in non-neoplastic cysts such as goblet cell metaplasia that was present in our case is an important feature to be included in the differential diagnosis and not to be interpreted as a mucinous neoplasm, particularly on fine-needle aspiration specimen microscopic evaluation that would impact further management. Here we describe the diagnosis and treatment of lymphoepithelial cysts in a patient who was on highly active antiretroviral therapy for HIV infection and we provide a brief literature review. Defining the clinical characteristics of lymphoepithelial cysts in patients with HIV and determining accurate preoperative diagnostic procedures will be critical for establishing effective surgical and medical approaches to treating these cysts, which differ substantially from other more serious pancreatic cystic lesions.

BRD3-NUTM1-expressing NUT carcinoma of lung on endobronchial ultrasound-guided transbronchial needle aspiration cytology, a diagnostic pitfall.

BACKGROUND: Nuclear protein in testis (NUT) carcinoma (NC) is an aggressive type of poorly differentiated carcinoma with a variable degree of squamous differentiation. NC is defined by the presence of BRD-NUT fusion oncogenes, the most common fusion form being the BRD4-NUTM1 gene. Variant rearrangements involving the BRD3 and NSD3 genes. Variant rearrangements involving the BRD3 and NSD3 genes occur in approximately one-third of the cases. AIMS: This is the first case regarding the study of cytological features of NC of the lung with BRD3-NUTM1 fusion. MATERIALS AND METHODS: A 36-year-old female with chest heaviness and shortness of breath was found to have a right-sided pleural effusion; she was non-smoker and denied any significant past medical illness. CT-chest revealed an 8.5 cm heterogeneous mass in the right and mid-upper lung. She underwent endobronchial ultrasound-guided (EBUS) transbronchial fine-needle aspiration (FNA) of the lung mass. Thoracocentesis was performed, and pleural fluid was sent to the laboratory for cytological evaluation RESULTS: The cytopathological findings showed atypical squamoid cells with variably prominent single or multiple nucleoli. Monotonous-looking cells with high nuclear to cytoplasmic ratio and hyperchromasia were also present. The atypical squamoid cells showed abundant clear to eosinophilic cytoplasm with rare individual cell keratinization and focal keratin pearl formation. The atypical cells were positive for CK7, p40, p63, mCEA and equivocal for NUT-specific antibody. The cytopathological findings were consistent with squamous cell carcinoma with focal keratinization. The Fusion Panel-Solid Tumor (50 genes) revealed BRD3-NUTM1 fusion gene. Diagnosis was amended to pulmonary NC. DISCUSSION: NC is a diagnostic challenge for pathologists as it can morphologically mimic undifferentiated carcinoma, squamous cell carcinoma, or neuroendocrine carcinoma. The challenge is not how to diagnose NC but rather determining when to include it in the differential diagnosis and perform the diagnostic molecular tests (FISH or NGS) or IHC study for NUT-specific antibody. CONCLUSION: When a specimen demonstrates a dual cell population of squamoid cells and primitive-looking tumor cells in the wrong clinical context (i.e., young patient with no smoking history), further molecular profiling is warranted to include the differential of a primary NC of the lung. The cytological features of NC itself have rarely been documented and moreover, that of a primary NC of the lung with BRD3-NUTM1 fusion has never been reported. We herein report cytological findings of a primary NC of the lung with BRD3-NUTM1 fusion gene.

P-selectin expression assay in a repeatedly serotonin-release assay-negative patient with heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) is an immune complication of heparin therapy caused by antibodies to complexes of platelet factor 4 (PF4) and heparin. Pathogenic antibodies to PF4/heparin bind and activate platelets to propagate a hypercoagulable state culminating in life-threatening thrombosis. The serotonin-release assay (SRA) is considered the gold-standard test to diagnose HIT. However, the sensitivity of the SRA was questioned with reported cases of clinical diagnosis of HIT and negative SRA. Herein, we present the utility of platelet factor 4-dependent P-selectin expression assay (PEA) in diagnosing HIT in a patient with thrombocytopenia and recurrent thrombosis who repeatedly tested negative with SRA.

Rhabdomyosarcoma with epithelioid morphology: A challenging cytologic diagnosis in a pleural effusion.

Rhabdomyosarcomas (RMS) are rare malignant skeletal muscle tumors that present more commonly in pediatric populations. The WHO currently classifies RMS into four types, embryonal, alveolar, pleomorphic, and spindle cell/sclerosing variants. Epithelioid rhabdomyosarcoma (EpiRMS) is another rare, recently described subtype of RMS presenting in older patients with a male predominance and has a rapidly progressive clinical course with frequent metastases. EpiRMS closely mimics poorly differentiated carcinoma or melanoma, demonstrating discohesive large epithelioid cells with abundant eosinophilic cytoplasm, frequent glassy cytoplasmic inclusions, large vesicular nuclei, and prominent nucleoli. We present a case of metastatic rhabdomyosarcoma with features reminiscent of EpiRMS presenting as a pleural effusion, closely followed by an inguinal lymph node biopsy. The malignant cells in the pleural fluid were diffusely positive for desmin, negative for MyoD1, myogenin, S100 and SOX10, and retained INI-1 expression. Subsequent lymph node biopsy demonstrated identical malignant epithelioid cells that were positive for desmin, myoD1 and myogenin, and a cytological diagnosis of "metastatic rhabdomyosarcoma, favor epithelioid rhabdomyosarcoma" was given considering the concurrent lymph node biopsy morphology and immunoprofile. A diagnosis of rhabdomyosarcoma, though rare and challenging, should not be overlooked when considering malignant cells with an epithelioid morphology in cytology specimens.

Xanthogranulomatous Ureteritis Mimicking Ureteral Involvement by Cancer in a Radical Cystectomy Specimen.

Xanthogranulomatous pyelonephritis is well established as a renal mass-forming inflammatory process. However, a ureteral counterpart is minimally recognized. In this article, we present a case of xanthogranulomatous ureteritis in an 81-year-old woman, mimicking ureteral involvement by cancer in a radical cystectomy specimen for invasive urothelial carcinoma. Similar to the pathogenesis of xanthogranulomatous pyelonephritis, the patient was noted to have ureteral obstruction by calculus and had urine culture positive for Klebsiella pneumoniae. To our knowledge, this is the first report of xanthogranulomatous ureteritis associated with this pathogen and the only report associated with concurrent bladder cancer. Increased pathologist and urologist awareness of xanthogranulomatous ureteritis expands the spectrum of pseudotumoral processes of the ureter.

Paradoxical embolic strokes in a liver transplant recipient with atrial septal defect undergoing therapeutic plasma exchange.

Therapeutic plasma exchange (TPE) is a technique used to separate blood components into layers based on their density difference, thus removing plasma and exchanging it with replacement fluids. A variety of adverse reactions has been described during TPE. Thrombotic events, especially strokes, are extremely rare complications of TPE. Our patient was a 55-year-old female with history of decompensated nonalcoholic steatohepatitis (NASH) liver cirrhosis. She underwent an orthotopic liver transplant (OLT) that was complicated with asystole during reperfusion. Cardiac workup revealed a new atrial septal defect (ASD) with left to right flow. Within the first 5 days after surgery, she developed refractory and persistent hyperbilirubinemia, with total bilirubin levels as high as 42 mg/dL. Our plasmapheresis service was consulted to initiate TPE. Towards the end of the first and only session of TPE, the patient developed hypoxia and left-sided hemiplegia. Stroke response was initiated, and the patient was intubated. MRI done 24 hours after the incident showed multiple acute small embolic infarcts scattered within the bilateral cerebral and cerebellar hemispheres. Bilateral lower and upper extremities venous duplex studies were positive for acute left internal jugular (IJ) vein thrombosis. Patient was treated with anticoagulation and the IJ catheter was removed. Patient also had closure of her ASD. On last follow up, she was doing well with complete reversal of neurologic deficits and stable liver function. Our patient had an uncommon complication of TPE. Her thrombosis manifested with multiple embolic strokes that would not have happened without an ASD with left to right flow.