Human Pathology: Case Reports最新文献

Leydig cell tumor is an uncommon and often benign sex-cord stromal tumor of the testis. We present a case of a 64-year old with a testicular mass with uncharacteristically high-grade cytology and ultrasound imaging which after excision was diagnosed as an LCT and pathologically staged as T1M0.  Literature review suggested that features observed in this tumor (high mitotic rate, necrosis, atypical nuclear features, ultrasonographic heterogeneity), may place it among the 10% of LCTs that are malignant, yet its staging proved otherwise.  Hence, we set out to describe this tumor in detail and review the differential diagnosis.  The immunohistochemical profile of this tumor (positive for alpha-inhibin, calretinin, Melan-A, and cytokeratin AE1/AE3, and negative for OCT4 and podoplanin) proved valuable in making the diagnosis.

Here we present a case of a 75-year-old man with an incidentally discovered anterior mediastinal mass, which on resection showed histologic features of both type A and micronodular thymoma with lymphoid stroma (MNT). MNT is a rare variant of thymoma with a characteristic appearance of distinct nodules of epithelial cells with few interspersed lymphocytes surrounded by abundant lymphoid stroma that lacks epithelial cells. We discuss features of this tumor and compare similar cases reported in the literature.

On a mid-summer day, a middle-aged man with severe pectus excavatum died unexpectedly in his bed one to two weeks after the onset of dyspnea, which had been followed by bedrest and restricted drinking and eating. Computed tomography (CT) and autopsy demonstrated an eccentrically hypertrophied heart (weight 600 g), which was displaced, rotated, and occupied a large space in the left thoracic cavity due to a deeply depressed sternum. The pulmonary artery was bent and extended across the left thoracic cavity to the right hilum. Anatomical abnormalities in the heart and pulmonary artery obstructed the right ventricular outflow, dilated the right ventricle, and induced restrictive hemodynamics. The left lung was atelectatic due to compression by the heart, while the right lung was enlarged and partly expanded to the left upper thoracic cavity. Histology confirmed pulmonary infarctions at different stages in the upper and middle lobes of the right lung. Restrictive hemodynamics promoted right ventricular dilation, causing spatial limitation of the left thoracic cavity. It is presumed that diastolic right ventricular dysfunction would have rapidly progressed along with pericardial effusion (150 mL), and intra-cardiac thrombi were formed due to stagnation, arrhythmia, bedrest, and dehydration. Consequently, the thrombi would be repetitively embolized in the right lung, thereby aggravating respiratory dysfunction and right-sided heart failure. This is the first autopsy report on the unexpected death of an untreated adult patient of pectus excavatum, with systematic pathophysiological analyses on the basis of the postmortem CT, macroscopic, and microscopic findings.

We describe a novel pathology finding in a 40-year-old woman without a history of breast carcinoma who presented with axillary swelling. The patient underwent core needle biopsy followed by axillary dissection 6 months later. The core biopsy of the axillary mass was initially considered to be a carcinoma of unknown primary, and as the biopsy specimen showed a pleomorphic malignant neoplasm that was GATA3 positive, the working diagnosis became metastatic breast carcinoma. The patient underwent an axillary dissection and was referred to our center for continuation of care. In addition to being positive for GATA3, the neoplasm was positive for CD21, CD23 and CD35, and negative for keratins, EMA, mammaglobin GCDFP-15, CD138, S-100 protein and other markers. The diagnosis of follicular dendritic cell sarcoma was established. We believe it is important to be aware that follicular dendritic cell sarcoma can be positive for GATA3, to avoid misdiagnosis as a metastatic neoplasm and an exhaustive workup for a primary site.

Nodular fasciitis is often misdiagnosed as its histological mimics, including malignant tumors, due to high levels of cellularity and the presence of occasional mitotic figures. A 15-year-old boy noticed a mass on his left shoulder and was admitted to the hospital. Based on magnetic resonance imaging (MRI) results, the lesion seemed to be located within the muscle, just below the subcutaneous adipose tissue and adjacent to the periosteum of the left humerus. It showed an iso-low signal on T1-weighted images, a heterogeneously high signal on T2-weighted images, and a hyperintense signal on T2 fat-suppression. A fascial tail sign was observed in T2 and T2 fat-suppression sagittal slices. Although the lesion was diagnosed as nodular fasciitis by biopsy, the lesion gradually increased in size up to 3.7 cm during 2 months of follow up after the first admission. The lesion was surgically resected with the marginal margin. Histological analysis showed fascicular proliferation of spindle-shaped cells with inflammatory infiltrates and stromal bleeding. A diagnosis of nodular fasciitis was confirmed by the detection of an MYH-USP6 fusion transcript. The identification of this fusion gene helped to avoid an unnecessary surgical procedure. The patient has been followed up for 6 months after surgery without any evidence of recurrence.

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma and is often treated with chemotherapy, autologous stem cell transplant, and chimeric antigen receptor (CAR-T) cell therapy. Despite the increasing use of CAR-T therapy in various hematolymphoid malignancies, very little is known about pathologic effects on various tissues. We report a case of diffuse large B-cell lymphoma treated with CAR-T, with suspected relapse on PET scan. Pathology from an excisional biopsy showed no evidence of persistent diffuse large B-cell lymphoma, but instead showed extensive deposition of PAS positive, acellular material, consistent with proteinaceous lymphadenopathy. There is little known pathologic effects on malignant tissue following CAR-T therapy and we present one such undocumented finding of post-CAR-T cell therapy-induced proteinaceous lymphadenopathy.

Introduction

Arachnoid cyst, a congenital extra-axial lesion, has been implicated in osteolytic lesion and subdural hematoma. Cerebral venous thrombosis occasionally induces subdural hematoma.

Case report

A man in his mid-forties with congenital bone defects was found dead after recumbency for months. Autopsy disclosed acute subdural hemorrhage and intracranial hemorrhage that infiltrated to the right neck through large occipital bone defects. CT demonstrateda high density area in the supratentorial venous sinuses and an infratentorial low-density mass adjacent to the bone defects, suggesting cerebral venous thrombosis and arachnoid cysts, respectively.

Conclusion

This is the first report on death due to nontraumatic extracranial and subdural hemorrhage derived from cerebral venous sinuses and possibly associated with arachnoid cysts and cerebral venous thrombosis.

Since the discovery of the ETV6-NTRK3 gene fusion in infantile fibrosarcoma two decades ago, it has become an important diagnostic marker because it is found in the majority of cases. However, the development of new molecular tests, including next generation sequencing, has uncovered additional gene fusions and other oncogenic mutations in tumors with the clinical and morphologic features of infantile fibrosarcoma. We present a case of infantile fibrosarcoma harboring a novel BMPR1A-RAF1 fusion and having a favorable outcome 6 years after surgery. This new structural alteration adds to the list of genetic aberrations in infantile fibrosarcoma and provides another example of the challenge of reconciling classic morphology with novel molecular genetics.

Mantle cell lymphoma (MCL) is an aggressive B cell lymphoma and characterized by the t(11;14)(q13;q32)/CCND1+. MALT1 amplification is the most common genetic event in MALT lymphomas. Identification of CCND1 and MALT1 gene over expression plays a key role in the diagnosis of MCL and some MALT lymphomas. Several unusual variants of MCL have been described with variable morphological, immunophenotypic and genetic characteristics. Here, we report an unusual nasopharyngeal B cell lymphoma with both CCND1 rearrangement and MALT1 amplification. The patient was a 60 year old gentleman admitted for further evaluation of “unspecified lymphoma”. PET oncology study revealed intense FDG avidity in the nasopharyngeal region, highly suspicious for malignancy. A biopsy of nasopharyngeal lesion was performed. Histological examination showed focal expansion of mantle zone surrounding residual germinal centers. Flow cytometry demonstrated one population of monoclonal B cells, negative for CD23 with variable CD5 expression. Lymphocytes in mantle zone were positive for CD20, BCL1 and weakly CD5 by immunohistochemistry. Interestingly, FISH studies were positive for standard and variant IGH/CCND1 rearrangement (85%) and MALT1 gene amplification (60%). Staging evaluations showed minimal bone marrow lymphoma involvement and increased FDG avidity in bilateral tonsillar regions and regional nodes of the neck, indicative of systemic disease. The overall findings were consistent with primary nasopharyngeal mantle cell lymphoma, which harbored both CCND1 and MALT1, with systemic involvement. The patient responded well with chemotherapy. To our knowledge, this is the first such case reported in the literature. Recent studies have shown that MALT1 gene may involve in the MYC pathway regulation in MCL, which represents a promising target for future therapies in MCL patients.

Low grade adenosquamous carcinoma (LGAC) is an uncommon variant of metaplastic “triple negative” breast cancer with clinical-radiologic characteristics and histopathology which overlaps with other entities such as syringomatous adenoma. We report a case of LGAC in a woman in her 40s who presented with breast pain. An irregular hypoechoic retroareolar mass was identified on mammogram. Biopsy showed nests of cells with squamoid appearance and compressed “tadpole-shaped” glandular structures embedded in dense collagenous stroma with lymphoid aggregates. The tumor cells were highlighted by CK7 and squamous component by CK5/6 and p63 and were ER, PR and HER2 negative. The morphologic and immunophenotypic features were consistent with LGAC. Genetic study found she was heterozygous for the p.R798* pathogenic germline mutation in BRIP1 gene. Patient underwent excision and managed with adjuvant radiation alone post operatively. This is the first LGAC reported with BRIP1 mutation and we emphasize characteristics in diagnosis, differential diagnosis and management for LGAC in this report.