Unclassifiable renal carcinoma with medullary phenotype and SMARCB1 deficiency: case report

BackgroundRenal medullary carcinoma (RMC) is an aggressive tumor representing less than 0.5% of renal cell carcinomas (RCC), and it is considered rare. When it occurs, patients typically have sickle cell trait, sickle cell disease, or an associated hemoglobinopathy, which is a necessary characterist...

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Main Authors: Samya H. Mehanna, Thiago Gabriel Ronkoski, Cassiano Machado, Lucas S. Wolff, Alexandre C. Cavalli, Thiago Hota, Fernando C. Koleski
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-06-01
Series:Frontiers in Urology
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Online Access:https://www.frontiersin.org/articles/10.3389/fruro.2025.1582675/full
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author Samya H. Mehanna
Thiago Gabriel Ronkoski
Cassiano Machado
Lucas S. Wolff
Alexandre C. Cavalli
Thiago Hota
Fernando C. Koleski
author_facet Samya H. Mehanna
Thiago Gabriel Ronkoski
Cassiano Machado
Lucas S. Wolff
Alexandre C. Cavalli
Thiago Hota
Fernando C. Koleski
author_sort Samya H. Mehanna
collection DOAJ
description BackgroundRenal medullary carcinoma (RMC) is an aggressive tumor representing less than 0.5% of renal cell carcinomas (RCC), and it is considered rare. When it occurs, patients typically have sickle cell trait, sickle cell disease, or an associated hemoglobinopathy, which is a necessary characteristic for diagnosis. Additionally, RMC is characterized by the inactivation of alterations in the SMARCB1 (INI1) tumor suppressor gene, resulting in the loss of INI1 immunohistochemical expression. However, there are tumors reported in the literature with the same morphological and phenotypic characteristics as RMC but without hemoglobinopathy, referred to as “unclassified RCC with medullary phenotype.”Case reportWe present the 13th case of unclassified renal cell carcinoma with a medullary phenotype in a 20-year-old woman. The patient was admitted with complaints of macroscopic hematuria, with no significant findings on physical examination. Diagnostic investigation included a computed tomography urogram, which revealed a hypovascular oval image with central cystic/necrotic areas in the middle third of the right kidney, measuring 32 mm, suggesting a possible diagnosis of an infected renal cyst. Subsequent magnetic resonance imaging showed findings consistent with an atypical presentation of primary neoplasia in the differential diagnosis, prompting a renal biopsy for case definition. Histopathological analysis revealed a high-grade infiltrative epithelioid neoplasm. Immunohistochemistry showed positivity for PAX8 and loss of INI-1 expression. No hemoglobinopathies were identified in the patient, in this context, the neoplasm is appropriately classified as unclassified renal cell carcinoma (RCC) with medullary phenotype and SMARCB1 deficiency. The instituted therapy consisted of right radical nephrectomy with retroperitoneal lymphadenectomy, with nodal metastases detected.ConclusionGiven the rarity of unclassified RCC with a medullary phenotype, continuous documentation and analysis of individual cases not associated with sickle cell trait are crucial to understanding its behavior, prognosis, and potential therapeutic approaches, considering its aggressiveness and high metastatic potential.
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spelling doaj-art-e66411efe24042e8a7b581cd1b5bd46b2025-08-20T03:24:38ZengFrontiers Media S.A.Frontiers in Urology2673-98282025-06-01510.3389/fruro.2025.15826751582675Unclassifiable renal carcinoma with medullary phenotype and SMARCB1 deficiency: case reportSamya H. Mehanna0Thiago Gabriel Ronkoski1Cassiano Machado2Lucas S. Wolff3Alexandre C. Cavalli4Thiago Hota5Fernando C. Koleski6Department of Pathology, Nossa Senhora das Graças Hospital, CURITIBA-PR, Curitiba, BrazilFaculdade Evangélica do Paraná, Curitiba-PR, BrazilDepartment of Urology, Nossa Senhora das Graças Hospital, Curitiba-PR, BrazilDepartment of Urology, Nossa Senhora das Graças Hospital, Curitiba-PR, BrazilDepartment of Urology, Nossa Senhora das Graças Hospital, Curitiba-PR, BrazilDepartment of Urology, Nossa Senhora das Graças Hospital, Curitiba-PR, BrazilDepartment of Urology, Nossa Senhora das Graças Hospital, Curitiba-PR, BrazilBackgroundRenal medullary carcinoma (RMC) is an aggressive tumor representing less than 0.5% of renal cell carcinomas (RCC), and it is considered rare. When it occurs, patients typically have sickle cell trait, sickle cell disease, or an associated hemoglobinopathy, which is a necessary characteristic for diagnosis. Additionally, RMC is characterized by the inactivation of alterations in the SMARCB1 (INI1) tumor suppressor gene, resulting in the loss of INI1 immunohistochemical expression. However, there are tumors reported in the literature with the same morphological and phenotypic characteristics as RMC but without hemoglobinopathy, referred to as “unclassified RCC with medullary phenotype.”Case reportWe present the 13th case of unclassified renal cell carcinoma with a medullary phenotype in a 20-year-old woman. The patient was admitted with complaints of macroscopic hematuria, with no significant findings on physical examination. Diagnostic investigation included a computed tomography urogram, which revealed a hypovascular oval image with central cystic/necrotic areas in the middle third of the right kidney, measuring 32 mm, suggesting a possible diagnosis of an infected renal cyst. Subsequent magnetic resonance imaging showed findings consistent with an atypical presentation of primary neoplasia in the differential diagnosis, prompting a renal biopsy for case definition. Histopathological analysis revealed a high-grade infiltrative epithelioid neoplasm. Immunohistochemistry showed positivity for PAX8 and loss of INI-1 expression. No hemoglobinopathies were identified in the patient, in this context, the neoplasm is appropriately classified as unclassified renal cell carcinoma (RCC) with medullary phenotype and SMARCB1 deficiency. The instituted therapy consisted of right radical nephrectomy with retroperitoneal lymphadenectomy, with nodal metastases detected.ConclusionGiven the rarity of unclassified RCC with a medullary phenotype, continuous documentation and analysis of individual cases not associated with sickle cell trait are crucial to understanding its behavior, prognosis, and potential therapeutic approaches, considering its aggressiveness and high metastatic potential.https://www.frontiersin.org/articles/10.3389/fruro.2025.1582675/fullrenal cell carcinomarenal medullary carcinomaINI1 deficiencyphenotypehemoglobinopathy
spellingShingle Samya H. Mehanna
Thiago Gabriel Ronkoski
Cassiano Machado
Lucas S. Wolff
Alexandre C. Cavalli
Thiago Hota
Fernando C. Koleski
Unclassifiable renal carcinoma with medullary phenotype and SMARCB1 deficiency: case report
Frontiers in Urology
renal cell carcinoma
renal medullary carcinoma
INI1 deficiency
phenotype
hemoglobinopathy
title Unclassifiable renal carcinoma with medullary phenotype and SMARCB1 deficiency: case report
title_full Unclassifiable renal carcinoma with medullary phenotype and SMARCB1 deficiency: case report
title_fullStr Unclassifiable renal carcinoma with medullary phenotype and SMARCB1 deficiency: case report
title_full_unstemmed Unclassifiable renal carcinoma with medullary phenotype and SMARCB1 deficiency: case report
title_short Unclassifiable renal carcinoma with medullary phenotype and SMARCB1 deficiency: case report
title_sort unclassifiable renal carcinoma with medullary phenotype and smarcb1 deficiency case report
topic renal cell carcinoma
renal medullary carcinoma
INI1 deficiency
phenotype
hemoglobinopathy
url https://www.frontiersin.org/articles/10.3389/fruro.2025.1582675/full
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