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[A case of mesothelioma of perinephric space origin]
Abstract:
Cystic mesothelioma of perinephric retroperitoneum origin are very uncommon tumors and considered potentially malignant. We report one such case and discuss the clinical and pathological findings. A 70-year-old man was seen with complaint of discomfort in the right flank and hospitalized in May 1989. Computerized tomography revealed multiple cystic masses in the right retroperitoneal space which appeared to be infiltrating the kidney and the iliopsoas muscles. Magnetic resonance imaging showed deformation of the right kidney with many impressions in the parenchyma. The cystic lesions and the right kidney were extirpated on June 2, 1989. Grossly the specimen was 16 x 10 x 8 cm in size and 630 g in weight. The multiple cysts surrounding the kidney were each approximately 10 mm in diameter and had thin outer walls. The cyst fluid was clear and serous. The kidney had not been infiltrated but had only external impressions caused by the cystic lesions. Microscopically, the cysts were lined by a single layer of cuboidal cells accompanied by some hobnail-shaped cells, and no evidence of malignancy was found. The epithelium was focally positive for periodate acid Schiff and slightly positive for Alcian blue. It was strongly positive for cytokeratin and vimentin, and slightly positive for EMA but negative for lectins. The diagnosis was diffused benign multicystic mesothelioma. However, CT taken four months after the operation revealed local recurrence and radiotherapy (40 Gy) was instituted. Since the cystic mass tended to grow in size thereafter, the lesion appeared to be malignant clinically. We consider this is the first case of cystic mesothelioma of perinephric retroperitoneum origin reported in Japan.
Insights
This case report details a rare benign multicystic mesothelioma in the retroperitoneum. Despite initial benign pathology, local recurrence after surgery suggested malignancy, highlighting diagnostic challenges.
Area of Science:
- Oncology
- Pathology
- Radiology
Background:
- Cystic mesothelioma of the retroperitoneum is an exceptionally rare tumor with potential for malignancy.
- This report presents a unique case originating in the perinephric retroperitoneum.
Observation:
- A 70-year-old male presented with flank discomfort, revealing multiple retroperitoneal cystic masses on CT and MRI.
- Imaging suggested infiltration of the kidney and iliopsoas muscles, though surgical exploration showed only external impressions on the kidney.
Findings:
- Microscopic examination confirmed a diffused benign multicystic mesothelioma, lined by cuboidal and hobnail cells.
- Immunohistochemistry showed positivity for cytokeratin and vimentin, with focal positivity for PAS and Alcian blue.
Implications:
- Local recurrence four months post-surgery, treated with radiotherapy, led to clinical suspicion of malignancy.
- This case highlights the diagnostic and clinical management challenges of rare retroperitoneal cystic lesions, particularly concerning potential recurrence and malignant transformation.