Renal cell carcinoma - chromophobe-like in the setting of Lynch syndrome
Presentation
Patient with no significant past medical history presents to the ER with worsening back pain and urinary urgency. CT was performed for further evaluation.
Patient Data
Routine post-contrast CT images during a predominantly late arterial phase demonstrate an 8.3 cm expansile mass in the superior pole of the left kidney. The mass enhances homogeneously to a lesser degree than the adjacent renal parenchyma and demonstrates a central stellate-shaped region of low attenuation/hypoenhancement.
Case Discussion
Patient subsequently underwent left radical nephrectomy. Pathology revealed a "Chromophobe-like" renal cell carcinoma. The tumour had features resembling chromophobe renal cell carcinoma, however immunohistochemical staining was not typical (negative CD117). Tumours with such features have been reported in patients with tuberous sclerosis complex, however patient did not have clinical features of TSC, such as history of seizures, mental retardation, or skin lesions. Patient underwent genetic testing which was positive for a pathogenic 1.2kb deletion of exons 13-14 in the PMS2 gene compatible with Lynch syndrome.
Key points:
the least common main subtype of RCC
similar to oncocytomas. Well defined with homogenous enhancement, less so than clear cell RCC, with occasional central scar
associated with Birt-Hogg-Dube syndrome
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