PMC9846587_01
Chemical shift magnetic resonance imaging (MRI) showing a heterogeneous
adrenal mass with a diameter of 23 mm. The adrenal mass showed a mottled
loss of signal intensity from the in-phase (a) to opposed-phase (b) MR
images.
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Magnetic resonance imaging (MRI) revealed a heterogeneous left adrenal mass with a diameter of 23 mm (Figure 1). 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy did not indicate increased uptake in the adrenal mass.
(a) Positional relationship of the adrenocortical adenoma (arrow) and
micro-pheochromocytoma (arrowhead). Sectional views of (b) the
adrenocortical adenoma and (c) the micro-pheochromocytoma. (d)
Hematoxylin-eosin (HE) staining of the adrenocortical adenoma (x200). Clear
cells and dense cells coexisted. (e) Lipomatous changes were observed in
some parts of the adenoma (x40). (f) HE staining of the
micro-pheochromocytoma (x20). (g) HE staining of the micro-pheochromocytoma
(x200). (h) Chromogranin A expression of the micro-pheochromocytoma (x200).
(i) Positive reactivity for MIB-1 was found in less than 1% of the
micro-pheochromocytoma (x400).
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The final pathology revealed an adrenocortical adenoma measuring 26 x 24 mm, in which clear and dense cells coexisted (Figure 2a, b, and d). Lipomatous changes were observed in some adenoma areas (Figure 2e). In addition to the adrenocortical adenoma, a small nodule, 3 x 2 mm in size, was incidentally found in the ipsilateral adrenal medulla (Figure 2a, c, and f). Chromogranin A-positive atypical medulla cells proliferated and were arranged in the "zellballen" pattern (Figure 2g and h). The Ki67 labeling index was <1% (Figure 2i).
Immunohistochemical staining of the micro-pheochromocytoma with (a) tyrosine
hydroxylase (TH), (b) aromatic L-amino acid decarboxylase (AADC), (c)
dopamine beta-hydroxylase (DBH), and (d) phenylethanolamine N-methyltransferase
(PNMT) antibodies (x100). The primary antibodies were mouse monoclonal
antibodies: anti-TH, F-11, sc-25269; anti-DDC, 8E8, sc-293287; and
anti-PNMT, C-7, sc-393995, from Santa Cruz Biotechnology, Dallas, USA, and
the anti-DBH goat polyclonal antibody, ab189991, from Abcam plc, Cambridge,
UK. Dashed lines show boundaries between the normal adrenal medulla (m) and
micro-pheochromocytoma (p). The letter c indicates the adrenal cortex.
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Abcam plc, Cambridge, UK), and phenylethanolamine N-methyltransferase (PNMT; C-7, sc-393995, Santa Cruz Biotechnology) were performed. All of these enzymes were detected in the micro-PCC (Figure 3).
Catecholamine biosynthetic enzyme expression in the normal medulla and
micro-pheochromocytoma (PCC). Values are shown as percentages of the stained
area. Panels (a), (b), (c), and (d) correspond to those in Figure 3.
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The intensity of anti-TH staining was higher in the micro-PCC lesion than in the normal medulla (Figure 4a), whereas the intensity of anti-DBH, AADC, and PNMT staining did not differ significantly between these 2 regions (Figure 4b-d).