[rare subtype of kidney cancer - Pigmented microcystic chromophobe carcinoma].

AIM: Chromophobe renal cell carcinoma (chRCC) is a morphologically heterogeneous tumor type, with one of its rarest forms being pigmented microcystic chromophobe carcinoma.

METHODS

In our paper, we present the case of a 68-year-old man, in whom imaging studies identified a 32 mm kidney tumor.

RESULTS

The tumor was surgically removed, and pathological analysis revealed a cystic tumor with unusual morphology, composed of eosinophilic cells. Brown pigment and hemorrhage were present in the lumen of the cysts. Immunohistochemically, the tumor showed diffuse CD117, PAX8, and E-cadherin expression, with focal positivity for CK7 and CD10. GATA3, MelanA, HMB45, cathepsin K, CK20, chromogranin A, and synaptophysin reactions were negative. Chromosome 17 monosomy could not be detected using double-labeled HER2/cen17 chromogenic in situ hybridization. The patient recovered well after the operation and is currently under oncological care.

CONCLUSIONS

To the best of our knowledge, this is the first documented case of pigmented microcystic chromophobe carcinoma diagnosed in Hungary. The aim of this paper is primarily to raise awareness, and in the course of our work, we will review the morphological subtypes of chRCC and the differential diagnostic entities.