It has become important to evaluate the possible involvement of 3β-hydroxysteroid dehydrogenase type 1 (HSD3B1) and 2 (HSD3B2) isoforms in aldosterone-producing adenoma (APA). In this study, we studied 67 and 100 APA cases using real-time quantitative PCR (qPCR) and immunohistochemistry, respectively. Results of qPCR analysis demonstrated that HSD3B2 mRNA was significantly more abundant than HSD3B1 mRNA (P < 0.0001), but only HSD3B1 mRNA significantly correlated with CYP11B2 (aldosterone synthase) mRNA (P < 0.0001) and plasma aldosterone concentration (PAC) of the patients (P < 0.0001). Results of immunohistochemistry subsequently revealed that HSD3B2 immunoreactivity was detected in the great majority of APA but a significant correlation was also detected between HSD3B1 and CYP11B2 (P < 0.0001). In KCNJ5 mutated APA, CYP11B2 mRNA (P < 0.0001) and HSD3B1 mRNA (P = 0.011) were significantly higher than those of wild type APA. These results suggest that HSD3B1 is involved in aldosterone production, despite its lower levels of expression compared with HSD3B2, and also possibly associated with KCNJ5 mutation in APA.

Renal epithelioid angiomyolipoma (EAML) is a potentially malignant tumor type whose characteristics and biomarkers predictive of malignant behavior have not been elucidated. Here, we report three cases of renal EAML with malignant features but without histories of tuberous sclerosis complex. Case 1 involved a 29-year-old man with a 12-cm solid mass in the right kidney who underwent radical right nephrectomy. Case 2 involved a 22-year-old woman with a retroperitoneal mass who underwent radical right nephrectomy and retroperitoneal tumorectomy. Local recurrence was detected 7 years post-surgery. Case 3 involved a 23-year-old man with a 14-cm solid mass in the left kidney who underwent radical left nephrectomy. Microscopically, the tumors in all cases demonstrated proliferation of epithelioid cells with atypia, mitotic activity, necrosis, hemorrhage, and vascular invasion. Epithelioid cells in all cases were immunohistochemically positive for melanocytic and myoid markers and weakly positive for E-cadherin and β-catenin. Immunohistochemistry revealed activation of the mammalian target of rapamycin pathway. Here, we report the morphological and immunohistochemical features of clinically or histologically malignant renal EAML.

The great majority of the cases clinically diagnosed as primary aldosteronism (PA) have been caused by aldosterone-producing adenoma (APA) or idiopathic hyperaldosteronism (IHA). The differential diagnosis of both subtypes of PA is important due to the different therapeutic modes but clinically it is sometimes difficult. It is also important to understand the morphological features of these two subtypes with special emphasis upon differences of the status for aldosterone biosynthesis. In the last decade, molecular mechanisms of PA including the aberrant expression of G-protein coupled receptors (GPCRs), key regulators of the intracellular calcium signaling pathway and somatic mutations of ion channels, have been revealed and our understanding of the molecular pathways involved in excessive aldosterone production has been markedly advanced. In addition, newly developed monoclonal antibodies specific to the isoform of adrenal steroidogenic enzymes have demonstrated the novel profiles of adrenal steroidogenesis in PA. These novel findings indicate that the molecular mechanisms on the onset and pathophysiology of PA are more complicated than previously considered and further clarification of clinical relevance of these findings is required at this juncture.

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In chromaffin cells, tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC), dopamine β-hydroxylase (DBH), and phenylethanolamine N-methyltransferase (PNMT) are mainly involved in catecholamine synthesis. In this study, we evaluated the association between the status of catecholamine-synthesizing enzymes and histopathological features of pheochromocytoma and extraadrenal paraganglioma with special emphasis upon their postoperative clinical behavior. Immunohistochemical evaluation of TH, DBH, AADC, PNMT, Ki 67, and S-100 was performed in 29 pheochromocytoma and 10 extraadrenal paraganglioma and one lymph node harboring metastatic pheochromocytoma. Among these cases, metastasis was subsequently developed in three cases. Urinary normetanephrine (U-NM) levels were significantly higher in clinical metastatic cases than non-metastatic ones. Ki 67 labeling index was significantly higher in both clinical metastatic cases and the Adrenal Gland Scaled Score (PASS) score of ≧ 4 cases than PASS < 4 cases, although this score was originally used in pheochromocytoma. H-score of AADC and DBH were significantly lower in PASS ≧ 4 cases than those with < 4 cases, and in the cases associated with intratumoral necrosis (n = 4), the presence of spindle shaped tumor cells (n = 4), and large nests of cells or diffuse growth (n = 5). Lower status of intratumoral AADC could be related to poor differentiation of tumor cells in both catecholamine production and morphology and could be related to aggressive biological behavior of both pheochromocytoma and extraadrenal paraganglioma.