Human Pathology: Case Reports最新文献

The World Health Organization (WHO) recognizes aggressive natural killer (NK)-cell leukemia and extranodal NK/T-cell lymphoma, nasal type as Epstein Barr Virus (EBV) associated lymphoproliferative disorders that may have overlapping features and must be distinguished from other T-cell lymphomas. A 35-year-old Hispanic female presented with fever of unknown origin, hemolysis and pancytopenia. Bone marrow biopsy with flow cytometry was negative for malignancy. Jejunal resection was performed due to concern for perforation and demonstrated a high-grade lymphoid neoplasm. Immunohistochemical stains showed that the neoplastic cells are positive for CD3, CD30, CD56 and cytotoxic markers Granzyme and TIA-1. EBV encoded RNA (EBER) was strongly positive in neoplastic cells. The location and immunophenotype first raised consideration of intestinal T-cell lymphoma, not otherwise specified (NOS). However, EBER positivity is characteristic of extranodal NK/T-cell lymphoma, nasal-type involving the small bowel. The patient soon expired and autopsy demonstrated hepatosplenomegaly with scattered nodules of necrosis with neoplastic cells morphologically similar to those in the jejunum and involving the hepatic sinusoids and splenic red pulp. Overlapping morphology and immunophenotype, lack of specific cytogenetic and molecular abnormalities makes the diagnosis of EBV associated extranodal NK/T cell leukemia/lymphomas challenging. EBER studies are mandatory to differentiate from Intestinal T cell lymphoma NOS. Early diagnosis of this aggressive malignancy is crucial in expediting appropriate treatment.

Nuchal-type fibroma is a rare benign fibrous tumor that is mainly located in the nuchal region. However, about one-third of the tumors occur in the extranuchal region. This tumor has specific histopathologic findings; it is composed of dense paucicellular, sclerotic, thick and haphazardly arranged collagen fibers. We report a 58-year-old man who presented with perineal nuchal-type fibroma originating in the perirectal region. This tumor was surgically excised; however, the fibrous band from tumor reached into levator ani muscle and was resected incompletely. Continuous follow up is needed even though this tumor is benign.

Monophasic epithelial synovial sarcoma is extremely rare, and its existence has been debated. We report a case of monophasic epithelial synovial sarcoma, which was initially diagnosed as metastatic adenocarcinoma. A 45-year-old woman presented with a tender pelvic mass, whose morphology was consistent with a glandular neoplasm. The mass was misdiagnosed as metastatic adenocarcinoma of unknown primary, and was treated as such. The tumor recurred 12 years later; it showed biphasic morphology including glandular and spindle sarcomatoid components. TLE1 immunoreactivity of the second tumor supported diagnosis of biphasic synovial sarcoma. The original lesion was reexamined and revealed very focal minor spindle tumor foci admixed with an extensive glandular background. The TLE1 immunostain was strongly positive in the initial lesion, thus confirming diagnosis of epithelial-predominant synovial sarcoma. This case emphasizes the importance of generous sampling and the use of TLE1 staining when soft tissue tumors show predominantly epithelial architectures without an apparent primary site.

Metastatic well-differentiated neuroendocrine tumors in the breast are rare and can be mistaken as invasive breast carcinoma due to their overlapping clinical, histological or radiological features. A 49-year-old female presented for evaluation of a left breast mass. Her past medical history was significant for an ileal well-differentiated neuroendocrine tumor with liver metastasis. Histology of breast biopsy shows nests of small uniform tumor cells with regularly dispersed chromatin. The tumor cells are positive for synaptophysin, chromogranin, CDX2, and ER (weak); and negative for CK7 and GATA3. These immunophenotypic features, in conjunction with the clinical history and cellular morphology, support the diagnosis of metastatic well-differentiated neuroendocrine tumor with ileal origin. Considering her asymptomatic breast lesion and indolent liver metastasis, she was offered close follow up and elective lumpectomy. This case reinforces the importance of recognizing a metastatic neuroendocrine tumor in the breast to ensure appropriate treatments.

Metanephric adenoma is an uncommon benign renal neoplasm which typically occurs in the adult population. Although calcification is a common finding, osseous metaplasia is uncommon and may cause diagnostic difficulty on preoperative radiological imaging. Bone marrow elements (i.e. haematopoietic cells and adipose tissue) have been described in renal cell carcinomas but to our knowledge not in metanephric adenoma. We present a case of a 75-year-old woman diagnosed with a metanephric adenoma with the unusual finding of associated bone and bone marrow elements. To our knowledge, this is the first case report of bone marrow elements seen in association with metanephric adenoma.

Primary intestinal NK-cell lymphoma (PINKL) is a rare entity with an overall poor prognosis. It is frequently EBV-positive and is characteristically negative for a T-cell gene rearrangement. Some parameters that may confer a relatively good prognosis include unifocality, the absence of intestinal perforation, and possibly EBV negativity. While exceedingly rare case reports of EBV-negative PINKL are available in the literature, the NK-cell phenotype of these lymphomas is determined solely by negative T-cell gene rearrangement studies. To the best of our knowledge, there has been no report of an EBV-negative PINKL that is defined by both flow cytometric evidence of absent surface CD3 expression as well as a negative T-cell gene rearrangement study. Furthermore, these reports do not include cytogenetic studies and/or next-generation sequencing (NGS) mutational analysis of the lymphoma. Thus, herein, we report a novel case of a stage I EBV-negative PINKL with an NK-cell phenotype confirmed by both flow cytometric immunophenotyping and a negative T-cell clonality study, describe its cytogenetic and next-generation sequencing (NGS) mutational profile, highlight the clinical course of the patient's 26-month follow-up, and review the relevant literature. The distinctive clinicopathologic findings of this case may expand our knowledge in understanding the biology of EBV-negative NK-cell lymphomas, which may differ from their EBV-positive counterparts.

Synovial sarcoma is a tumor commonly involves extremities and periarticular soft tissue of young adults. Head and neck region is involved in 10% of cases, mostly biphasic in histology. Submandibular gland is an uncommon anatomic location for primary synovial sarcoma. Herein, we present a unique case of primary submandibular gland synovial sarcoma morphologically mimicking a solitary fibrous tumor. Moreover, the neoplastic cells reveal an aberrant p63 nuclear expression. The immunoprofile and the molecular studies confirmed TLE1 expression and SYT (18-11.2) rearrangement, respectively. To the best of our knowledge, the present case is the first with a p63 expression and the second reported case of primary submandibular gland synovial sarcoma in English literature.

Extranodal Rosai-Dorfman disease (RDD) of the kidney is rare, with unknown etiology. We present a case of extranodal RDD of the kidney. Imaging revealed a nodular lesion in the right renal pelvis, with accompanying pelvic dilation and parenchymal atrophy, reminiscent of immunoglobulin G4 (IgG4)-related disease. With the clinical diagnosis of suspected renal pelvic cancer, laparoscopic right nephrectomy was performed. Macroscopic findings showed a mass with a white-tan cut surface. Histological examination revealed histiocytes with emperipolesis and patchy infiltration of plasma cells, lymphocytes and foamy macrophages in a fibrocollagenous stroma. Immunohistochemically, the histiocytes were positive for S100, CD68 and CD163, but negative for CD1a, p80/ALK and phospho-p44/42 MARK (Thr202/Tyr204). IgG4-positive plasma cells were not evident.

These findings indicated that the lesion represented extranodal RDD of the kidney. No mutations of the K- and N-RAS genes could be identified in this case. Although rare, extranodal RDD should be included in the differential diagnosis of a renal pelvic mass.

Mantle cell lymphoma is characterized by the presence of the t(11;14)(q13;q32), which is found in more than 95% of cases. We present a case of mantle cell lymphoma with the typical phenotype, which transformed to a blastic morphology with loss of expression of CD20, CD5 and BCL2, and gain of CD10 and TdT. In cases presenting with blastic morphology, the use of CD10 and TdT in addition to the usual mantle cell lymphoma markers is essential since cases of mantle cell lymphoma with B-lymphoblastic features may require innovative treatment.