Metastatic clear cell renal carcinoma without evidence of a primary renal tumour mimicking advanced stage of malignant lung tumour
Abstract
Background: Clear cell renal carcinoma (ccRC) accounts for 65-70% of renal carcinomas with peak occurrence at the 6th and 7th age decade, predominantly in males. At the time of dia gnosis, especially pulmonary metastases can be found in one-third of patients.
There have also been described as late metastases for several decades after nephrectomy. In our case report, clinical course indicated primary lung tumour.
Histological diff erential dia gnosis included malignant pleural mesothelioma, lung adenocarcinoma and squamous cell carcinoma with clear cell diff erentiation or primary clear cell adenocarcinoma of the lung. However, using immunohistochemistry, all these possible dia gnoses were excluded.
Case report: We present a case of 62-year old man with 3 months history of progressive dyspnea accompanied with a cough and recurrent pleural eff usions. PET/ CT scan revealed metastatic tumour spread with right-sided pleural thickening, multiple pulmonary tumour foci, mediastinal, cervical, abdominal para-aortic and pelvic lymph node involvement and skeletal metastasis.
The patient died one day after administration of palliative chemotherapy. The autopsy showed the majority of changes in the right hemithorax, was caused by a diff use yellowish, extremely tough tumour infi ltrating parietal and visceral pleura with adhesions and obliteration of truncus pulmonalis.
In left lung and both renal cortices we could see scant nodules, mimicking primary lung tumour metastasis. In close proximity to the left renal hilum we found unusual homogeneous white round to oval tissue of 80 x 86 x 72 mm in diameter, with identical histological pattern.
Extensive immunohistochemical profi le (positivity of CK18, PAX8, vimentin, androgen receptor, napsin A; negativity of mesothelial markers, TTF-1, CK7, CK20, CDX-2, CD10, PSA, CK34B12 and PAS-D) was compatible with metastatic ccRC. Conclusion: We present an extremely rare case of morphologically verifi ed metastatic ccRC without evidence of primary lesion in the kidneys.
There is speculated the possibility of spontaneous regression of primary tumour. In our case, however, we cannot exclude the possibility of generalized primary tumour of ectopic kidney.
This hypothesis is based on the fi nding of isolated tumour mass adjacent to left renal hilum. (C) 2019 Klinicka Onkologie. All rights reserved.