Renal sclerosing peritubular nodules in a patient with neurofibromatosis type 2: a case report with immunohistochemical and electron microscopic studies.

Kidney lesions in patients with von Recklinghausen typically include blood vessels with smooth muscle proliferation resulting in hypertension, and perirenal nerve sheath tumors. In the English language literature, there is only 1 report published more than 25 years ago that described a previously unrecognized renal parenchymal lesion, termed sclerosing peritubular nodules, in 3 members of a family affected by von Recklinghausen disease. These nodules were examined by light microscopy, histochemistry, and electron microscopy; they proved to be derived from interstitial cells, and the proliferating cells showed myofibroblastic differentiation by electron microscopy. We report a case of a 22-year-old man with hereditary neurofibromatosis type 2 who died with complications of the disease. He underwent autopsy, and his kidneys showed this unique lesion. We examined these peritubular proliferations with immunohistochemistry, histochemistry, and electron microscopy and compared our findings with the previous report in the literature.