# Metastatic Clear Cell Carcinoma of Unknown Primary Origin in an Elderly Female Patient With Paraneoplastic Hypercalcemia

## TL;DR

A rare case of metastatic clear cell carcinoma of unknown origin in an elderly woman is presented, highlighting the challenges in diagnosing and treating such cancers.

## Contribution

This paper contributes a rare clinical case of metastatic clear cell carcinoma with unknown primary origin and discusses its diagnostic and therapeutic challenges.

## Key findings

- The patient's biopsy suggested possible renal or ovarian origins but could not confirm the primary site.
- The aggressive nature of mCCC led to the patient's death before chemotherapy could be administered.
- Empiric chemotherapy is standard for CUP but lacks sufficient data for effective management.

## Abstract

Metastatic clear cell carcinoma (mCCC) is a rare histological subtype of cancer with ovarian and renal origins most common primary sites. Cancer of unknown primary origin (CUP) is a rare type of cancer in the United States and the most common histologic subtypes are adenocarcinoma, squamous cell cancer, and neuroendocrine cancer. We are presenting a rare case of an 86-year-old female patient with mCCC of unknown origin, biopsy and staining showed renal and ovarian in the differential of primary cancer type. However, the patient did not survive the aggressive nature of mCCC and was unable to get any trials of chemotherapy. Primary sites of adenocarcinoma of unknown origin are most common in the breast, lung, pancreas, prostate, colon, and liver. In most cases, empiric chemotherapy with platinum-based agents is the standard of care but needs more data to manage CUP, making it difficult to identify the primary site.