Multinucleate Cell Angiohistiocytoma Workup

Updated: Nov 07, 2019
  • Author: Diane M Scott, MD; Chief Editor: William D James, MD  more...
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Lesions of multinucleate cell angiohistiocytoma often mimic other conditions. A biopsy is the best way to exclude more serious disorders (eg, sarcoidosis, Kaposi sarcoma). [17]


Histologic Findings

Multinucleate cell angiohistiocytoma has a distinctive histologic appearance characterized by a vascular proliferation and bizarre multinucleated cells. In the upper and mid dermis, a proliferation of small blood vessels occurs, some of which have dilated lumina. The vessels have the histologic appearances of capillaries and small vessels. The endothelial cells lining the vessels are plump but lack atypia. A sparse perivascular lymphocytic infiltrate may be present. In addition, an increased number of mast cells has been reported.

The vascular proliferation is embedded in a fibrous stroma rich in fibrohistiocytic cells. The collagen bundles are slightly thickened and arranged haphazardly or parallel to the epidermis. Bizarre multinucleated cells are amongst the interstitial cells. These cells have 3-10 hyperchromatic nuclei that are closely aggregated or arranged in a ringlike fashion. The cytoplasm of these cells is often angulated or scalloped in outline (see the images below).

Biopsy specimen of multinucleate cell angiohistioc Biopsy specimen of multinucleate cell angiohistiocytoma. A vascular proliferation is embedded in a stroma rich in fibroblasts and histiocytes, some of which are multinucleated.
Bizarre multinucleated cells are present in the st Bizarre multinucleated cells are present in the stroma surrounding the vascular proliferation.

Immunohistochemical studies may be useful in confirming the diagnosis of multinucleate cell angiohistiocytoma and in differentiating it from other vascular and fibrous proliferations. The lesional vessels label with factor VIII–related antigen (factor VIII-RA), EN-4, BMA-120, PAL-E, and Ulex europaeus agglutinin I (UEA-I). These findings indicate a capillary and venular nature of the vessels. Polymerase chain reaction analysis reveals no evidence of human herpesvirus-8 (HHV-8) infection, as may be found in Kaposi sarcoma.

The multinucleated cells stain with vimentin, but they do not label with the macrophage markers lysozyme, MAC 387, and alpha-1-antitrypsin. The multinucleated cells are also negative for S-100 protein, factor XIII, and human leukocyte antigen DR (HLA-DR). The mononuclear interstitial cells label with vimentin, factor XIIIa, and CD68.