A unique presentation of renal cell transformation into renal cell carcinoma in subcutaneous fatty tissue post twenty year old healing gun-shot wound: A case report.

INTRODUCTION: Renal cell carcinoma (RCC) is the most common malignancy in the genitourinary tract, and is among the 10 most common cancers in both males and females.

PRESENTATION OF CASE: We report a case of a 61-year-old male who presented with a cutaneous lesion on his left back side at a site where he had undergone several surgeries - including Left nephrectomy - twenty years ago for a gun-shot wound he sustained which penetrated his abdomen.

DISCUSSION: At that time pathology reports turned out to be normal, specially left kidney pathology report which was negative for any malignancy. Twenty years later, patient presented with a clear fluctuating painless cutaneous mass of 1-2cm on his left back side, which grew gradually over time. Histopathologically, the incisional biopsy showed trabecular & papillary clear cells with prominent vascularity and hemosiderin deposition in the stroma, consistent with a malignant Renal cell Carcinoma (RCC). Immunohistochemically, it stained positive for Vimentin, CD10, PAX-8. Labs revealed positive renal cell carcinoma antibody. CT scans, urine tests, and bone scans failed to reveal the site of the primary lesion. Furthermore, the patient reports minimal constitutional symptoms and is grossly well.

CONCLUSION: The authors have reported an interesting case of an RCC presenting in a healed gun-shot wound in a previously nephrectomized patient. To the best of authors' knowledge, such a case hasn't been reported in the literature before, with it being unique in its time course, preceding events, and absence of primary lesions.