Spindle and Cuboidal Renal Cell Carcinoma (Loopom). Descriptionof 13 cases

Overview

Background.
Current classification systems of neoplasms arising from renal parenchyma distinguish 5 categoriesof renal cell carcinoma (RCC), i.e. conventional RCC, papillary RCC, chromophobe RCC, collecting duct/medullaryRCC and unclassified RCC. We present 13 cases of unusual and unclassified spindle and cuboidal renal cellcarcinomas.Methods and Results. The studied group consisted of 13 patients (7 men and 6 women). They ranged in age from22 to 65 years (mean 57.3). Generally, the tumours were well circumscribed and confined to the kidney, whitish togrey on section with a diameter 4,5–13 cm (mean 8.6 cm). One patient was investigated for loin pain and nocturia.Three patients had staghorn nephrolithiasis and vague sonographic findings in renal parenchyma. In one patient therenal tumour was found when examined on follow-up examination for prostatic adenocarcinoma.None of our patientswas known to have elevated levels of parathyroid hormone due to hyperplasia, adenoma or carcinoma of theparathyroid gland. Clinical follow-up of the patients ranged from 9 months to 8 years (mean 2.3 years). Microscopically,the tumours were composed of two main populations of cells: flattened, spindle cells with sparse cytoplasmand small cuboidal cells with clear to light eosinophilic cytoplasm. Eight patients are currently well without signsof recurrence or metastasis, one had metastasis in the regional lymph node at the time of nephrectomy, one died ofunrelated cause, and three were lost to follow-up.Conclusions. We present 13 cases of unclassified RCC. Our cases were histologically, immunohistochemically andultrastructurally similar to the hitherto reported case reports of this variant of RCC. It is obvious, that that variantof RCC should be recognised as a new subtype of RCC.

Key words:
kidney, renal cell carcinoma, unclassified, spindle cell carcinoma.