Case Number : Case 2379 - 8 August 2019 Posted By: Arti Bakshi

IHC data on CAIX and CK 7 needed with a history of Clear cell RCC

At first glance, it seems obviously a metastatic clear cell renal cell carcinoma. The clinical history and the histological pictures are pretty suggestive of RCC metastasis. But there is a history of a benign adnexial tumor in the axilla 3 years ago. Looking closer, we do not see the classical vasculature of RCC. There are reports of a rare nodal clear cell hidradenoma wich could be primary nodal or secondary to a "benign" metastasis. IHQ with PAX-8, RCC, p63 and keratin 5/6 could help in this differentiation.

4 hours ago, IgorSC said:

At first glance, it seems obviously a metastatic clear cell renal cell carcinoma. The clinical history and the histological pictures are pretty suggestive of RCC metastasis. But there is a history of a benign adnexial tumor in the axilla 3 years ago. Looking closer, we do not see the classical vasculature of RCC. There are reports of a rare nodal clear cell hidradenoma wich could be primary nodal or secondary to a "benign" metastasis. IHQ with PAX-8, RCC, p63 and keratin 5/6 could help in this differentiation.

Agree. Lymph node involvement by clear cell nodular hidradenoma is known. In last image, there appears to be a cystic/duct like structure with apocrine type lining. IHC needed to differentiate from RCC. 

Agree with above.  There aren’t erythrocytes between clear cell nests and there is an obvious apocrine cystic change in last fig.  Thinking of a Low grade hydradenocarcinoma.  

Agree looks like hidradenoma in a LN.