OBJECTIVETo study the clinicopathologic features, immunophenotype, differential diagnosis and prognosis of renal cell carcinoma (RCC) associated with t(6;11)(p21.2;q13)/MALAT1-TFEB gene fusion.

METHODSA total of 9 cases of such rare tumor were selected for clinicopathologic, immunohistochemical and molecular analysis, with review of literature.

RESULTSThe age of the patients ranged from 21 to 42 years (mean=31.3 years). The patients included four men and five women. Histologically, 4 of the 9 cases studied showed classic morphologic features of TFEB RCC, with hyaline material, pigments and psammoma bodies frequently identified. The remaining 5 cases demonstrated uncommon morphology, mimicking perivascular epithelioid cell neoplasm, clear cell RCC, chromophobe RCC or papillary RCC. Immunohistochemical study showed that TFEB and vimentin were positive in all cases. Most of the tumors studied also expressed Ksp-cadherin, E-cadherin, CD117, HMB45, Melan A and Cathepsin K. CKpan showed immunostaining in only 1 case. The staining for TFE3, CD10 and CK7 were all negative. TFEB gene rearrangement was detected in all the 9 cases studied using fluorescence in-situ hybridization. MALAT1-TFEB fusion gene was identified in 2 cases by polymerase chain reaction and direct sequencing. TFEB RCC seemed to be an indolent tumor. During a mean follow-up of 31 months, none developed tumor recurrence, progression, or metastasis.

CONCLUSIONSTFEB fusion-associated RCC is a rare neoplasm, tends to occur in young age group and carries an indolent behavior. Diagnosis relies on clinicopathologic findings and immunohistochemical analysis. TFEB break-apart FISH assay is a reliable tool in confirming the diagnosis.

Adult ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors ; genetics ; Carcinoma, Renal Cell ; genetics ; pathology ; Chromosomes, Human, Pair 11 ; Chromosomes, Human, Pair 6 ; Diagnosis, Differential ; Female ; Gene Fusion ; Gene Rearrangement ; Genes, Neoplasm ; Humans ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Kidney Neoplasms ; genetics ; pathology ; Male ; Prognosis ; RNA, Long Noncoding ; genetics ; Translocation, Genetic ; Young Adult

OBJECTIVETo investigate the clinicopathologic features, immunohistochemic phenotypes and genetic alterations of extrapulmonary inflammatory myofibroblastic tumor (IMT) and the correlation with prognosis.

METHODSThirty cases of IMT with follow-up were analyzed morphologically and immunohistochemically. ALK FISH was also performed to determine the ALK gene status.

RESULTSPatients ranged in age from 12 to 73 years (mean 43.4 years). The male-to-female ratio was 1.0: 1.1. The tumors were located in various anatomical sites including gastrointestinal tract, liver, spleen, kidney, pelvic, retroperitoneum, mediastinum etc. Histologically, the majority of cases were composed of spindled fibroblastic and myofibroblastic cells accompanied by an inflammatory infiltrate of plasma cells, lymphocytes, and eosinophils. Most cases with aggressive behavior had features including prominent nucleoli and edematous myxoid background. Lymphohistiocytic reactions were usually absent. Some cases showed multinucleation, nuclear pleomorphism and mitoses. One case demonstrated epithelioid morphology with round-to-epithelioid cells. The immunohistochemical study showed vimentin, SMA, CK, desmin, and ALK were expressed in 100% (30/30), 70% (21/30), 13% (4/30), 27% (8/30), and 27% (8/30) of IMT, respectively. Diffuse cytoplasmic ALK staining was detected in seven cases. One case (containing round-to-epithelioid cells) demonstrated ALK nuclear membrane staining, coupled with positive reaction for CD30 and negative reaction for LCA. EMA, CD34, CD117 and S-100 protein, and MyoD1 were negative for all cases. Six ALK protein positive cases harbored ALK gene rearrangement, but not the remaining 22 cases. Follow-up data were available in 21 patients. After initial resection, 14 patients were alive with no evidence of disease, while 4 patients were alive with tumor recurrence and 3 patients died of the disease.

CONCLUSIONSMost IMT with aggressive behavior have features including prominent nucleoli, edematous myxoid background, and positive expression of ALK. Lymphohistiocytic reaction is usually absent. ALK may be a potential novel therapeutic target for IMT.

Adolescent ; Adult ; Aged ; Child ; Female ; Fibroblasts ; pathology ; Granuloma, Plasma Cell ; genetics ; pathology ; Humans ; Inflammation ; pathology ; Male ; Middle Aged ; Myofibroblasts ; pathology ; Prognosis ; Receptor Protein-Tyrosine Kinases ; genetics ; Young Adult

OBJECTIVETo study the clinicopathologic characteristics of primary renal hemangioblastoma.

METHODSThe morphologic features, immunophenotype and molecular findings of 3 cases of primary renal hemangioblastoma were studied, with review of literature.

RESULTSThe age of patients ranged from 43 to 57 years. There were 2 women and a man. The patients often presented with renal mass. Histologically, the tumors were surrounded by thick fibrous capsule and composed of epithelioid or spindle cells. Two cases had a prominent stromal component and the other one was rich in capillary network. Lipid vacuoles were observed in all cases. Features of hemorrhage were demonstrated in 2 cases. Capsular invasion and necrosis were seen in 1 case. Immunohistochemical study showed that the stromal cells were positive for alpha-inhibin (3/3), S-100 protein (3/3), EGFR (2/2), PAX-2 (2/2), PAX-8 (2/2) and CA9 (2/2) but negative for CKpan (2/2) and HMB45 (2/2). Focal membranous staining for CD10 (3/3) was noted. No VHL gene mutations or chromosome 3p deletion were detected in the 2 cases studied.

CONCLUSIONSRenal hemangioblastoma shows distinctive morphologic appearance with a wide range of variation. The unexpected positive staining for PAX-2, PAX-8 and CD10 in renal hemangioblastoma needs to be aware. Immunohistochemical study may be helpful in differential diagnosis of these renal tumors.