Journal of Pathology and Translational Medicine

Case Study

SDH-deficient renal cell carcinoma with intracytoplasmic mucinous material: a case report and literature review: Ryosuke Yoshioka, Kosuke Miyai, Kimi Kato, Keiichi Ito, Kimiya Sato, Susumu Matsukuma; J Pathol Transl Med. 2026;60(4):456-461. Published online July 15, 2026; DOI: https://doi.org/10.4132/jptm.2026.04.23

Abstract PDF: Succinate dehydrogenase (SDH)–deficient renal cell carcinoma (RCC) is a rare, molecularly defined neoplasm. We report a 45-year-old man with a right renal mass treated by nephrectomy. Grossly, a 38-mm gray-white-to-brown solid cystic tumor was observed in the lower pole of the kidney. Microscopically, the tumor consisted of sheets and nested proliferation of eosinophilic cells with low-grade nuclei and bubbly or flocculent cytoplasm. No sarcomatoid or rhabdoid features were observed. Abundant extracellular and focal intracytoplasmic mucinous material was observed in the tumor, which was positive for Alcian blue and mucicarmine staining, but negative for periodic acid–Schiff staining. Immunohistochemistry showed complete loss of succinate dehydrogenase subunit B in tumor cells. These findings supported the diagnosis of RCC consistent with SDH-deficient RCC. This case expands the morphological spectrum of SDH-deficient RCC and highlights the diagnostic pitfalls of renal tumors with mucinous material.

Original Article

Pathologic Findings of Mitochondrial Myopathy.: Lucia Kim, Tai Seung Kim; Korean J Pathol. 2000;34(1):77-84.

Abstract PDF: Mitochondrial myopathy (MM) has been applied to muscle disease in which mitochondria have abnormal structure, function or both. To characterize the pathologic findings of MM, we examined the ultrastructural and histochemical findings of 24 cases of MM. The ultrastructures of the MM were characterized by abnormal mitochondria in number (pleoconia) and size (megaconia), and showed predominant accumulation of mitochondria in the subsarcolemmal space of myofibers in all cases. Mitochondria contained abnormally shaped cristae (concentric form and gyriform) in 79% of cases. Paracrystalline inclusion which was known to be a characteristics of MM were seen only in 7 cases (29%). Electron dense deposits were more frequently found (77%) in abnormal mitochondria of chronic progressive external opthalmoplegia and Kearn-Sayre syndrome. But, other findings were not specific for the specific clinical entities. On succinate dehydrogenase (SDH) stain, ragged red fibers (RRF) showed more intense positivity than modified Gomori-trichrome stain and definite strong reactive products were present along the periphery of myofibers which showed normal findings on modified Gomori-trichrome stain. In conclusion, ultrastructural findings such as mitochondria showing pleoconia with megaconia, and bizarre shaped cristae may be helpful for the diagnosis of MM and SDH stain is more useful for identification of RRF than modified Gomori-trichrome stains.

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