Progesterone receptor expression in fibromuscular dysplasia: A report of two unusual cases

Abstract

Fibromuscular dysplasia is rarely biopsied. Progesterone receptor expression in myofibroblastic cells is useful for the histopathological evaluation in difficult-to-diagnose cases. Herein, we report two unusual cases of fibromuscular dysplasia in which progesterone receptor expression was shown in vessel sections.

Keywords: Fibromuscular dysplasia; coronary artery; popliteal artery; progesterone receptor; spontaneous coronary artery dissection..

Figure 1. (a, b) Tissue causing obstruction in popliteal artery. Nodular proliferation of disorganized fibroblasts and smooth muscle cells along with increased fibromyxoid connective tissue matrix. (H-E¥40). (c, d) Masson Trichrome stain showed that proliferation is mostly composed of collagen fibers; accompanying relatively decreased and disorganized smooth muscle cells (Masson Trichrome, ¥100, ¥40). (e) Elastic fibers discontinued in fibroblastic intimal layer (Weigert Van Gieson, ¥200). (f) Disorganization, splitting and destruction of elastic fibers through fibroblastic intima and superficial media layers (arrow) (Weigert Van Gieson, ¥40). (g) There is no staining in non-pathological vascular segment as a negative control tissue (IHC, 40XPR). (h) Nuclear PR positivity in cells of the tissue obstructing the vascular lumen (IHC, 200XPR)

Figure 2. (a) Dissection through thickened arterial vessel wall, organized hemorrhage, irregularity in elastic lamina (arrow) (H-E¥100). (b) Dissected intimal layer (asterix), intimal hyperplasia with fibroblastic/myofibroblastic cells and increased connective tissue matrix (H-E¥100). (c) Fibroplasia encompassing both intima and media; discontinuation of elastic lamina (arrow) (H-E¥200). (d) Increased collagen fibers with relatively diminished smooth muscle cells (Masson Trichrome, ¥100). (e) Destruction, splitting and partial loss of elastic fibers (Weigert Van Gieson, ¥100). (f) Nuclear PR positivity in smooth muscle cells and myofibroblastic cells within fibroblastic areas in intima and media of pathological vascular segment (IHC, 200XPR). (g) Angiography: Dissection of circumflex artery.