Abstract
Renal medullary carcinoma (RMC) is an extremely rare malignancy that has been described in younger male patients of African descent with a history of sickle cell disease or trait. We describe a rather unique case of RMC in an older male patient who initially presented with acute on chronic urinary retention and concern for infection. Further investigation revealed a history of hematuria and long-standing microcytic anemia, and the patient was found to have sickle cell trait (SCT) as part of a workup for malignancy of unknown primary. Imaging findings initially interpreted as hydronephrosis later characterized a mass in the renal pelvis concerning for a genitourinary malignancy, later biopsy-proven RMC. RMC typically presents in its advanced stages, with associated poor prognosis, and treatment options are limited and have been extrapolated from standard regimens for other genitourinary malignancies. Therefore, early clinical suspicion in patients with microcytic anemia, flank pain, hematuria, and urinary symptoms, can aid in the diagnosis of RMC and allow for prompt intervention.
Highlights
Renal medullary carcinoma (RMC) is a rare malignancy first described in 1995 as the “seventh sickle cell nephropathy,” with nearly 90% of cases reported to date associated with sickle cell trait (SCT) [1]
We present a rather unusual case of RMC in an older adult male with undiagnosed sickle cell trait and a clinical presentation of acute urinary retention and pyelonephritis with widespread suspected metastatic disease on imaging
Hematoxylin and eosin (H&E) staining (a) and immunohistochemical (IHC) staining for PAX8 (b) of the liver lesion specimen shows a PAX8+ poorly differentiated adenocarcinoma. (c) hematoxylin and eosin (H&E) staining of the kidney specimen at 10x magnification shows a high-grade carcinoma with a reticular architectural pattern and prominent desmoplasia. (d) H&E staining of the kidney specimen at 20x magnification demonstrates scattered sickled red blood cells, characteristic histologic findings of renal medullary carcinoma. (e) IHC for INI1 of the kidney specimen shows aberrant loss of staining in the tumor cells with retention in the background of non-neoplastic cells
Summary
Renal medullary carcinoma (RMC) is a rare malignancy first described in 1995 as the “seventh sickle cell nephropathy,” with nearly 90% of cases reported to date associated with sickle cell trait (SCT) [1]. The patient underwent an MRI, which showed a restricting left renal mass occupying the pelvis and extending into the lower pole of the left kidney at the site previously thought to represent hydronephrosis (Figures 1b-1d). Due to these imaging findings, IHC repeated on previous liver biopsy sample demonstrated loss of expression of INI1/SMARCB1 (integrase interactor 1/SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1), a known tumor suppressor gene located on chromosome 22q11.2. Hematoxylin and eosin (H&E) staining (a) and immunohistochemical (IHC) staining for PAX8 (b) of the liver lesion specimen shows a PAX8+ poorly differentiated adenocarcinoma. (c) H&E staining of the kidney specimen at 10x magnification shows a high-grade carcinoma with a reticular architectural pattern and prominent desmoplasia. (d) H&E staining of the kidney specimen at 20x magnification demonstrates scattered sickled red blood cells (arrows), characteristic histologic findings of renal medullary carcinoma. (e) IHC for INI1 of the kidney specimen shows aberrant loss of staining in the tumor cells with retention in the background of non-neoplastic cells
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
