Multinucleate cell angiohistiocytoma: A clinicopathologic study of 62 cases and proposed diagnostic criteria

Abstract

Background: Multinucleate cell angiohistiocytoma (MCAH) is an uncommon and likely underdiagnosed entity that is thought to be of vascular and fibrohistiocytic origin. Methods:We retrospectively reviewed all cases diagnosed as MCAH at the Yale Medicine Dermatopathology laboratory between 1 January 1990 and 1 September 2018. Sixty-two cases were retained. We performed immunohistochemistry on the ten most inflamed lesions found and assessed for a possible alteration within the Wnt/ß-catenin signaling pathway, involved in follicular induction in dermatofibroma.We subsequently established histologic diagnostic criteria to differentiate MCAH from its mimickers.Results: MCAH affected both genders equally. The hands or fingers were affected in 51.6% of cases. We found the most specific histologic criteria to be: (a) presence of odd multinucleated fibroblasts, (b) presence of superficial parallel fibrosis, (c) presence and thickening of superficial papillary dermal vessels, and (d) absence of perifollicular fibrosis. As for immunoreactivity, we found positivity to CD138, CD163, and CD117 in the mononuclear inflammatory infiltrate. There was no histopathologic evidence of follicular induction, as can be seen in dermatofibromas, and no expression of nuclear beta-catenin as seen in dermatofibromas with follicular induction.Conclusion: This large case series establishes MCAH as a distinct clinical and histopathologic entity. K E Y W O R D S epidemiology of multinucleate cell angiohistiocytoma, mast cells, multinucleate cell angiohistiocytoma, multinucleated giant cells, stellate fibroblasts

Cutaneous plasmacytosis and multinucleate cell angiohistiocytoma‐like lesion in a patient with hepatitis B: A fortuitous triad?

“…Plasma cells are evidently involved in CP, but may also be occasionally increased in number, around vessels in MCAH. 10 To conclude, cutaneous plasmacytosis is a rare infiltration of the skin by plasma cells, which may have been triggered the perpetual antigenic exposure in our patient with chronic hepatitis B. We believe the MCAH-like reaction pattern in the skin specimen to have been a reactive inflammatory process brought upon by either the plasmacytic infiltrate or the chronic hepatitis B.…”

“…In addition, the largest single‐institution review of MCAH (62 cases) had found indeed a single case in which MCAH was found to be associated with another disease (liver cirrhosis from chronic hepatitis C), yet, its clinical and histological presentation were different than the so‐called “classic MCAH.” The clinical presentation of our case was more representative of cutaneous plasmacytosis, given the brown‐purple plaques located on the axillae and groin. In contrast, MCAH usually presents as reddish‐brown papules and affects in around 50% of cases the hands or fingers . We believe MCAH may at times coexist with an associated systemic or local cutaneous disease, but that most cases arise spontaneously as a primary vascular/fibrohistiocytic process.…”

“…Roy et al had however found mast cell counts to be similar to the counts in normal or inflamed skin. Plasma cells are evidently involved in CP, but may also be occasionally increased in number, around vessels in MCAH …”

“…In contrast, MCAH usually presents as reddishbrown papules and affects in around 50% of cases the hands or fingers. 10 We believe MCAH may at times coexist with an associated systemic or local cutaneous disease, but that most cases arise spontaneously as a primary vascular/fibrohistiocytic process. Certain authors also view MCAH as a potential variant of dermatofibroma 11 while others view it as an entity sui generis.…”

“…Certain authors also view MCAH as a potential variant of dermatofibroma 11 while others view it as an entity sui generis. 10 Finally, a last possible link between these two cutaneous diseases may reside in the increase of mast cells or plasma cells in both conditions, which may have had a potentiating effect. In our patients' biopsies, mast cells were increased in samples which showed exclusively CP, but also in the stroma of the MCAH-like lesion.…”