Is renal medullary carcinoma the seventh nephropathy in sickle cell disease? A multi-center Nigerian survey.

Anazoeze Madu,Marcus Inyama,Obike Ibegbulam,Joseph Orkuma,Chikwudi Anigbo,Augustin Duru,Obineche Agwu,Uchenna Ololo,Charles Nonyelu,Malachy Iheanacho,Kaladada Korubo,Barth Chukwu,Caroline Omoti,Oluwaseun Akinpelu,Najibah Galadincci,Shehu Abdulahi,Iheanyi Okpala,Abdulaziz Hassan,Theresa Nwagha,Uche Anike,Garba Umar,Kingsley Akaba ,Emodi Ifeoma ,S Ocheni ,Alozie Uchenna Eze ,Okocha Emmanuel Chide ,Ugwu Angela ,An Ikefuna ,Fowodu O Florence

doi:10.4314/ahs.v16i2.17

Abstract

Previous studies had enlisted renal medullary carcinoma (RMC) as the seventh nephropathy in sickle cell disease (SCD). Clinical experience has contradicted this claim and this study is targeted at refuting or supporting this assumption. To estimate the prevalence of RMC and describe other renal complications in SCD. 14 physicians (haematologists and urologists) in 11 tertiary institutions across the country were collated from patients' case notes and hospital SCD registers. Of the 3,596 registered sickle patients, 2 (0.056%) had been diagnosed with RMC over a ten year period, thereby giving an estimated prevalence rate of 5.6 per 100,000. The most common renal complication reported by the attending physicians was chronic kidney disease (CKD). The frequency of routine renal screening for SCD patients varied widely between centres - most were done at diagnosis, annually or bi-annually. The ten year prevalence of RMC in Nigerian SCD patients was determined to be 5.6 (estimated incidence of 0.56). RMC is not more common in SCD patients and therefore cannot be regarded as a "Seventh Sickle nephropathy". Most of the managing physicians reported that the commonest nephropathy observed in their SCD patients was chronic kidney disease.

Highlights

Previous studies had enlisted renal medullary carcinoma (RMC) as the seventh nephropathy in sickle cell disease (SCD)
Renal medullary carcinoma was reported in 2 out of the 3,596 patients, making the 10 year prevalence rate 0.056%. Both cases were from the same center (Aminu Kano Teaching Hospital Kano), which had the largest pool of SCD patients – 1,800 registered patients
The 10 year prevalence of renal medullary carcinoma in sickle cell disease patients was found to 0.056%

Summary

Introduction

Previous studies had enlisted renal medullary carcinoma (RMC) as the seventh nephropathy in sickle cell disease (SCD). Conclusion: The ten year prevalence of RMC in Nigerian SCD patients was determined to be 5.6 (estimated incidence of 0.56). Previous reports had described RMC as a rare tumor of kidney that notably occurred in young African American patients with SCD4 or sickle cell trait, which they proposed to call the “seventh sickle cell nephropathy”[5,6]. Renal medullary carcinoma as a tumor is rare, very aggressive (with death often occurring within one year of diagnosis) and resistant to immunotherapy and chemotherapy. A possible relationship might be that chromosome 11 is involved in the development of renal medullary carcinoma

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