Ondřej Hes

Pure epithelioid PEComas (so-called epithelioid angiomyolipoma) of the kidney: A clinicopathologic study of 41 cases: detailed assessment of morphology and risk stratification.

Epithelioid angiomyolipomas (perivascular epithelioid cell tumors) of the kidney are defined as potentially malignant mesenchymal lesions that are closely related to classic angiomyolipoma. Although approximately 120 cases are published, mostly as case reports with variably used diagnostic criteria, the pathologic prognostic predictors of outcome are unknown. We analyzed the clinicopathologic parameters in a large series of 41 cases of pure epithelioid angiomyolipomas of the kidney, which we designate as pure (monotypic) epithelioid PEComas to contrast them from classic angiomyolipomas that are regarded by some as PEComas. We use the terminology “pure” to separate these cases from those that may have variable epithelioid components. The mean age of the patients was 40.7 years (range, 14 to 68 y). The male-to-female ratio was 1:1. Seventy-nine percent of patients were symptomatic at presentation with metastatic disease at onset in 12 cases. Follow-up and/or disease progression information were available for 33 of 41 cases (mean, 44.5 mo and median, 24.5 mo; range, 4 to 240); 9 patients had a history of associated tuberous sclerosis. Recurrence and metastasis were seen in 17% and 49% of patients; 33% of patients died of disease. Lymph node involvement was seen in 24% of patients; the liver (63%), lung (25%), and mesentery (18.8%) were the most common metastatic sites. Clinicopathologic parameters associated with disease progression (recurrence, metastasis, or death due to disease) in univariate analysis included associated tuberous sclerosis complex or concurrent angiomyolipoma (any metastasis, P=0.046), necrosis (metastasis at diagnosis, P=0.012), tumor size >7 cm (progression, P=0.021), extrarenal extension and/or renal vein involvement (progression, P=0.023), and carcinoma-like growth pattern (progression, P=0.040) (the 5 adverse prognostic parameters for pure epithelioid PEComas). Tumors with <2 adverse prognostic parameters (13 cases) were considered to be low risk for progression tumor, with 15% having disease progression. Tumors with 2 to 3 adverse prognostic parameters (14 cases) were considered to be “intermediate risk,” with 64% having disease progression. Tumors with more than 4 or more adverse prognostic parameters (6 cases) were considered to be high risk, with all patients having disease progression. Of tumors with 3 or more adverse prognostic parameters, 80% had disease progression. An exact logistic regression analytic model showed that only carcinoma-like growth pattern and extrarenal extension and/or renal vein involvement were significant predictors of outcome (P=0.009 and 0.033, respectively). Our data of a large series with uniform definitional criteria confirm the malignant potential for pure epithelioid PEComas and provide adverse prognostic parameters for risk stratification in these patients.

Cathepsin-K immunoreactivity distinguishes MiTF/TFE family renal translocation carcinomas from other renal carcinomas

The microphthalmia transcription factor/transcription factor E (TFE)-family translocation renal cell carcinomas bear specific translocations that result in overexpression of TFE3 or TFEB. TFE3 fusion gene product overexpression occurs as consequence of different translocations involving chromosome Xp11.2, whereas TFEB overexpression is the result of the specific translocation t(6;11)(p21;q12), which fuses the Alpha gene to TFEB. Both TFE3 and TFEB are closely related members of the microphthalmia transcription factor/TFE-family, which also includes TFEC and microphthalmia transcription factor. These transcription factors have overlapping transcriptional targets. Overexpression of microphthalmia transcription factor has been shown to mediate the expression of cathepsin-K in osteoclasts. We hypothesize that the overexpression of the related TFE3 fusion proteins and TFEB in translocation renal cell carcinomas may have the same effect. We studied cathepsin-K in 17 cytogenetically confirmed microphthalmia transcription factor/TFE-family translocation renal cell carcinomas. Seven cases showed a t(6;11)(p21;q12), ten cases showed translocations involving Xp11.2; five cases t(X;1)(p11;q21) resulting in a PRCC–TFE3 gene fusion; three cases t(X;1)(p11;p34) resulting in a PSF–TFE3 gene fusion, one t(X;17)(p11;q25) resulting in an ASPL–TFE3 gene fusion, and one t(X;3)(p11;q23) with an unknown TFE3 gene fusion. As control we analyzed cathepsin-K in 210 clear cell, 40 papillary, 25 chromophobe renal cell carcinomas and 30 oncocytomas. All seven TFEB translocation renal cell carcinomas were labeled for cathepsin-K. Among the cytogenetically confirmed TFE3 translocation renal cell carcinomas, 6 out of 10 were positive. None of the other renal neoplasms expressed cathepsin-K. We conclude the following: (1) cathepsin-K is consistently and strongly expressed in TFEB translocation renal cell carcinomas and in 6 of 10 TFE3 translocation renal cell carcinomas. (2) Cathepsin-K immunolabeling in both TFE3 and TFEB translocation renal cell carcinomas distinguishes these neoplasms from the more common adult renal cell carcinomas, and may be a specific marker of these neoplasms. (3) These results further support the concept that the overexpression of TFE3 or TFEB in these neoplasms activates the expression of genes normally regulated by microphthalmia transcription factor in other cell types.

Succinate Dehydrogenase (SDH)-deficient Renal Carcinoma: A Morphologically Distinct Entity: A Clinicopathologic Series of 36 Tumors From 27 Patients

Succinate dehydrogenase (SDH)-deficient renal carcinoma has been accepted as a provisional entity in the 2013 International Society of Urological Pathology Vancouver Classification. To further define its morphologic and clinical features, we studied a multi-institutional cohort of 36 SDH-deficient renal carcinomas from 27 patients, including 21 previously unreported cases. We estimate that 0.05% to 0.2% of all renal carcinomas are SDH deficient. Mean patient age at presentation was 37 years (range, 14 to 76 y), with a slight male predominance (M:F=1.7:1). Bilateral tumors were observed in 26% of patients. Thirty-four (94%) tumors demonstrated the previously reported morphology at least focally, which included: solid or focally cystic growth, uniform cytology with eosinophilic flocculent cytoplasm, intracytoplasmic vacuolations and inclusions, and round to oval low-grade nuclei. All 17 patients who underwent genetic testing for mutation in the SDH subunits demonstrated germline mutations (16 in SDHB and 1 in SDHC). Nine of 27 (33%) patients developed metastatic disease, 2 of them after prolonged follow-up (5.5 and 30 y). Seven of 10 patients (70%) with high-grade nuclei metastasized as did all 4 patients with coagulative necrosis. Two of 17 (12%) patients with low-grade nuclei metastasized, and both had unbiopsied contralateral tumors, which may have been the origin of the metastatic disease. In conclusion, SDH-deficient renal carcinoma is a rare and unique type of renal carcinoma, exhibiting stereotypical morphologic features in the great majority of cases and showing a strong relationship with SDH germline mutation. Although this tumor may undergo dedifferentiation and metastasize, sometimes after a prolonged delay, metastatic disease is rare in the absence of high-grade nuclear atypia or coagulative necrosis.

Spindle and cuboidal renal cell carcinoma, a tumour having frequent association with nephrolithiasis: report of 11 cases including a case with hybrid conventional renal cell carcinoma/ spindle and cuboidal renal cell carcinoma components

Aims:  We present the largest series of an unclassified subtype of renal cell carcinoma, which seems to be a distinct morphological entity and which is sometimes designated as spindle and cuboidal renal cell carcinoma.

Renal angiomyoadenomatous tumor: morphologic, immunohistochemical, and molecular genetic study of a distinct entity

We present a series of a distinct tumorous entity named renal angiomyoadenomatous tumor (RAT). Five cases were retrieved from the consultation files of the authors. Histologic and immunohistochemical features were evaluated. Sequencing analysis of coding region of the VHL gene was carried out in all cases. The tumors were composed of admixture of an epithelial clear cell component and prominent leiomyomatous stroma. Epithelial cells formed adenomatous tubular formations endowed with blister-like apical snouts. All tubular/glandular structures were lined by a fine capillary network. The epithelial component was positive for epithelial membrane antigen, CK7, CK20, AE1-AE3, CAM5.2, and vimentin in all cases. In all analyzed samples, no mutation of the VHL gene was found. RAT is a distinct morphologic entity, being different morphologically, immunohistochemically, and genetically from all renal tumors including conventional clear cell carcinoma and mixed epithelial and stromal tumor of kidney.

Collecting duct carcinoma versus renal medullary carcinoma: An appeal for nosologic and biological clarity

Mahul B. Amin, MD,* Steven C. Smith, MD, PhD,* Abbas Agaimy, MD,w Pedram Argani, MD,z Eva Marie Compérat, MD, PhD,y Brett Delahunt, MD, FRCPA, FRCPath,8 Jonathan I. Epstein, MD,z John N. Eble, MD,z David J. Grignon, MD,z Arndt Hartmann, MD,w Ondřej Hes, MD, PhD,# Michelle S. Hirsch, MD, PhD,** Rafael E. Jimenez, MD,ww Lakshmi P. Kunju, MD,zz Guido Martignoni, MD,yy Jesse K. McKenney, MD,88 Holger Moch, MD,zz Rodolfo Montironi, MD,## Gladell P. Paner, MD,*** Priya Rao, MD,www John R. Srigley, MD,zzz Satish K. Tickoo, MD,yyy and Victor E. Reuter, MDyyy

Tumours in End-Stage Kidney

OBJECTIVE Patients with end-stage kidney disease (ESKD) show a greater risk for renal cell carcinoma (RCC), which tends to be multifocal and bilateral. The malignant potential is unclear. The question is whether to remove both kidneys in patients with a tumor on one side only diagnosed by computed tomography (CT). MATERIALS AND METHODS Kidney tumors were found in 14 patients with ESKD from January 2002 to December 2006. One was unfit for surgery. Thirteen patients underwent nephrectomy and 6 a bilateral procedure of whom only 2 had bilateral tumors on CT, 3 multiple tumors on the contralateral side, and 1 uncontrollable hypertension with tumors as an incidental finding. Tumors were found in all 19 specimens. RESULTS In 13 kidneys (68.4%), the tumors were multiple; in 6 (31.6%), solitary. The types of tumor were: 13 (68.4%) papillary RCCs (PRCC), 9 (47.4%) clear RCCs (CRCC), a combination of PRCC and CRCC in 4 (21.0%), and myxoid liposarcoma (with solitary PRCC contralaterally). The mean follow-up was short (19 +/- 15 months; maximum, 54 months). Only 1 patient died due to a tumor at 16 months after operation. CONCLUSIONS There is a high risk for bilateral involvement. Patients who undergo unilateral nephrectomy must be regularly followed and contralateral nephrectomy carefully considered, mainly in transplanted patients on immunosuppression. Further studies are needed to give a definitive answer about the indications for surgery and the indications for contralateral nephrectomy as well. To date, prophylactic contralateral nephrectomy should not be a therapeutic standard.

Tubulocystic carcinoma of the kidney with poorly differentiated foci

An emerging group of high-grade renal cell carcinomas (RCCs), particularly carcinomas arising in the hereditary leiomyomatosis renal cell carcinoma syndrome (HLRCC), show fumarate hydratase (FH) gene mutation and loss of function. On the basis of similar cytomorphology and clinicopathologic features between these tumors and cases described as tubulocystic carcinomas with poorly differentiated foci (TC-PD) of infiltrative adenocarcinoma, we hypothesized a relationship between these entities. First, 29 RCCs with morphology of TC-PD were identified retrospectively and assessed for FH expression and aberrant succination (2SC) by immunohistochemistry (IHC), with targeted next-generation sequencing of 409 genes—including FH—performed on a subset. The 29 TC-PD RCCs included 21 males and 8 females, aged 16 to 86 years (median, 46), with tumors measuring 3 to 21 cm (median, 9) arising in the right (n=16) and left (n=13) kidneys. Family history or stigmata of HLRCC were identifiable only retrospectively in 3 (12%). These tumors were aggressive, with 79% showing perinephric extension, nodal involvement in 41%, and metastasis in 86%. Of these, 16 (55%) demonstrated loss of FH by IHC (14/14 with positive 2SC). In contrast, 5 (17%) showed a wild-type immunoprofile of FH+/2SC−. An intriguing group of 8 (28%) showed variable FH± positivity, but with strong/diffuse 2SC+. Next-generation sequencing revealed 8 cases with FH mutations, including 5 FH−/2SC+ and 3 FH±/2SC+ cases, but none in FH+/2SC− cases. Secondly, we retrospectively reviewed the morphology of 2 well-characterized cohorts of RCCs with FH-deficiency determined by IHC or sequencing (n=23 and n=9), unselected for TC-PD pattern, identifying the TC-PD morphology in 10 (31%). We conclude that RCCs with TC-PD morphology are enriched for FH deficiency, and we recommend additional workup, including referral to genetic counseling, for prospective cases. In addition, based on these and other observations, we propose the term “FH-deficient RCC” as a provisional term for tumors with a combination of suggestive morphology and immunophenotype but where genetic confirmation is unavailable upon diagnosis. This term will serve as a provisional nomenclature that will enable triage of individual cases for genetic counseling and testing, while designating these cases for prospective studies of their relationship to HLRCC.

Extensively Cystic Renal Neoplasms in Adults (Bosniak Classification II or III) – Possible “Common” Histological Diagnoses: Multilocular Cystic Renal Cell Carcinoma, Cystic Nephroma, and Mixed Epithelial and Stromal Tumor of the Kidney

Objective(s): To give an algorithm for resolution of extensively cystic renal neoplasms, preoperatively classified in the Bosniak classification as a category II and III. Methods: From 1991 to 6/2004, 701 patients with 727 renal tumours were surgically treated at our hospital. Extensively cystic tumours were found in 10 cases. Extensively cystic tumours were defined as multicystic tumours without any solid nodules visible neither on CT, nor grossly in the specimen at operation (the Bosniak classification type II or III). Results: Seven multilocular cystic renal cell carcinomas, three mixed epithelial and stromal tumour of the kidney and one cystic nephroma were diagnosed on histology. Conclusion(s): Extensively cystic renal tumours classified as the Bosniak type II or III correspond histologically to the entities mentioned above (multilocular cystic renal cell carcinoma, cystic nephroma, mixed epithelial and stromal tumour of the kidney). These entities cannot be distinguished one from another on preoperative imaging studies. A preoperative biopsy and intra-operative frozen-section analysis do not lead to a correct diagnosis in many cases. Fortunately, the operative strategy is the same for all these tumours. In such cases, the nephron sparing surgery is indicated, whenever technically feasible, as almost all extensively cystic renal tumours have a good prognosis.

Fumarate Hydratase-deficient Uterine Leiomyomas Occur in Both the Syndromic and Sporadic Settings.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) syndrome secondary to germline fumarate hydratase (FH) mutation presents with cutaneous and uterine leiomyomas, and a distinctive aggressive renal carcinoma. Identification of HLRCC patients presenting first with uterine leiomyomas may allow early intervention for renal carcinoma. We reviewed the morphology and immunohistochemical (IHC) findings in patients with uterine leiomyomas and confirmed or presumed HLRCC. IHC was also performed on a tissue microarray of unselected uterine leiomyomas and leiomyosarcomas. FH-deficient leiomyomas underwent Sanger and massively parallel sequencing on formalin-fixed paraffin-embedded tissue. All 5 patients with HLRCC had at least 1 FH-deficient leiomyoma: defined as completely negative FH staining with positive internal controls. One percent (12/1152) of unselected uterine leiomyomas but 0 of 88 leiomyosarcomas were FH deficient. FH-deficient leiomyoma patients were younger (42.7 vs. 48.8 y, P=0.024) and commonly demonstrated a distinctive hemangiopericytomatous vasculature. Other features reported to be associated with FH-deficient leiomyomas (hypercellularity, nuclear atypia, inclusion-like nucleoli, stromal edema) were inconstantly present. Somatic FH mutations were identified in 6 of 10 informative unselected FH-deficient leiomyomas. None of these mutations were found in the germline. We conclude that, while the great majority of patients with HLRCC will have FH-deficient leiomyomas, 1% of all uterine leiomyomas are FH deficient usually due to somatic inactivation. Although IHC screening for FH may have a role in confirming patients at high risk for hereditary disease before genetic testing, prospective identification of FH-deficient leiomyomas is of limited clinical benefit in screening unselected patients because of the relatively high incidence of somatic mutations.