Eosinophilic Solid and Cystic Renal Cell Carcinoma: From Unclassified to Classified, A Case Report.

Rashim Sharma,Mahaveer Singh Rodha,Balamurugan Thirunavukkarasu,Poonam Elhence,Binit Sureka

doi:10.5146/tjpath.2021.01531

Abstract

Eosinophilic solid and cystic renal cell carcinoma (ESC RCC) is a novel tumour with unique morphological and immunohistochemical features. It is a recently described entity after the 2016 World Health Organization Classification of Tumours of the Urinary System and Male Genital Organs and is characterised by a solid cystic tumour composed of polygonal cells with voluminous eosinophilic cytoplasm and CK20 positivity. This tumour has uncertain malignant potential and also has an association with tuberous sclerosis complex (TSC). Sarcomatoid differentiation has not been reported in ESC RCC till now. ESC RCC poses a diagnostic challenge as many eosinophilic/oncocytic renal tumours are included in the differentials. We present a case of ESC RCC with sarcomatoid differentiation in an elderly female without any clinical features of TSC and discuss the differential diagnosis of oncocytic renal tumours.

Highlights

Once described under unclassified RCC/eosinophilic/ oncocytic tumours, the characteristic features of Eosinophilic solid and cystic renal cell carcinoma (ESC RCC) were later described in a series illustrating the various RCC in patients with tuberous sclerosis (TSC associated RCC) [2,3]
Tumours with identical morphology were described in sporadic cases, exclusively in females [1]
Size of tumour in the present case was 19.5 cm which is the largest documented till date [1,2]

Summary

Introduction

Our understanding of renal tumours has significantly improved in the past years. This is due to advancements in the field of molecular pathology. An ill-circumscribed solid cystic tan brown, yellowish tumour was noted in the middle and inferior pole, abutting the capsule and measuring 19.5x14x9.5 cm (Figure 1C). The macrocysts were lined by round to polygonal tumour cells with eosinophilic granular cytoplasm, round nuclei, coarse to hyperchromatic nuclei and conspicuous nucleoli (Figure 2A,B). Tumour cells showed focal strong positivity for CK20 (Ks20.8, Thermofisher, RTU) predominantly in the cystic areas.

Results

Conclusion