Microscopic description:

Pleomorphic, oval shaped nuclei.

Clear cell appearance due to cytoplasmic vacuolization.

Eosinophilic staining cytoplasm with leishmania bodies (granular cytoplasmic stuppling).

Cells arranged in a compact nested pattern.

IHC: Positive for Pax8 (strong, nuclear, diffuse), MACR, CD10, CK20, SDHB; negative for MelanA, CAIX, CK7, CD117, ALK-1.

Based on histopathological feature and IHC stains, it is believed that the mass is eosinophilic solid and cystic type renal cell carcinoma.

Discussion:

Eosinophilic Solid and Cystic Type Renal Cell Carcinoma is an emerging subtype of renal cell carcinoma.

Predominantly affects females without a specific age range (has been found anywhere from from 14-75 years old).

Individuals usually present with painless hematuria and lack clinical symptoms associated with tuberous sclerosis complex.

There has been no evidence suggesting any clinical features or family history germline connections to tuberous sclerosis.

Believed to arise from sporadic tumors of renal neoplasms involving TSC1/2 genetic modifications (suppressor genes).

Grossly, features include solitary lesions and a well circumscribed border with yellow-tan nodules.

The IHC in the majority of cases will stain positive for AMACR, PAX8, and CK20; while staining can vary for CK7 (either presenting as focally positive or negative).

ESCRCC is rarely metastatic; however, there have been cases where it was noted to spread to the liver, lungs, adrenal glands, lymph nodes, and bone.

Non-metastatic cases treated with resection of mass or affected kidney.

In metastatic cases, mammalian target of rapamycin inhibitors have been used.

References:

Korentzelos, D. & Quiroga-Garza, G. (2021). Diagnosis -- Eosinophilic Solid and Cystic Renal Cell Carcinoma. A Case Report (1089). https://path.upmc.edu/cases/case1089/dx.html

Palsgrove, D., & Argani, P. (2021, May 25). Kidney Tumor: Eosinophilic, solid and cystic. Pathology Outlines. Retrieved from https://www.pathologyoutlines.com/topic/kidneytumorescrcc.html

Palsgrove, D., Li, Y., & Argani, P. (2019). EOSINOPHILIC SOLID AND CYSTIC (ESC) RENAL CELL CARCINOMAS HARBOR TSC MUTATIONS: MOLECULAR ANALYSIS SUPPORTS AN EXPANDING CLINICOPATHOLOGIC SPECTRUM. The American Journal of Surgical Pathology, 42(9), 1166–1181.

Sharma, R., Thirunavukkarasu, B., Elhence, P., Rodha, M. S., & Sureka, B. (2022). Eosinophilic Solid and Cystic Renal Cell Carcinoma: From Unclassified to Classified, A Case Report.Turk patoloji dergisi, 38(1), 60–65.

Tretiakova, M. (2018). Eosinophilic solid and cystic renal cell carcinoma mimicking epithelioid angiomyolipoma: series of 4 primary tumors and 2 metastases. Human Pathology, 80, 65–75.

Trpkov, K., Abou-Ouf, H., Hes, O., & Lopez, J. (2017). Eosinophilic Solid and Cystic Renal Cell Carcinoma (ESC RCC). The American Journal of Surgical Pathology, 41(10), 1299–1308.

CASE IMAGES