Letter to the Editor
To the Editor:
First described in 1985 by Smith and Wilson-Jones,1 multinucleate cells angiohistiocytoma (MCA) is a rare lesion considered to represent a benign vascular or fibrohistiocytic tumor.2 So far, around 55 cases have been reported in the literature. Most often occurring in middle-aged women, MCA is clinically characterized by multiple, red to violet papules usually located on the limbs, mainly on the legs or on the dorsum of the hands. Occasional cases were described on the face or chest, and one case in the oral mucosa has recently been reported.3 Papules often tend to regroup in the same anatomic site, and can measure up to 1.5 cm. The lesions develop over several years and then cease growth; few cases have demonstrated spontaneous regression. Microscopic examination reveals proliferation of small vessels associated with spindle or round fibroblast-like cells and peculiar multinucleated cells in the superficial and upper mid-dermis. The latter are angulated, star shaped, and feature up to 10 hyperchromatic nuclei and a basophilic cytoplasm. Vessels are well differentiated and usually lined by CD34-positive endothelial cells with prominent nuclei. The surrounding dermis shows a variable degree of fibrosis, with mast cells and foci of inflammation. The positive staining of fibroblastic cells for CD68 and Factor XIIIa prompted some authors to consider this lesion as a member of the fibrohistiocytic skin tumor group,4 although multinucleated cells, which are hallmark of the disease, are usually negative for both markers. However, histogenesis of these lesions remains largely unknown. Especially, whether it represents a neoplasm or a reactive process is a matter of debate. Due to its apparent rarity, literature about MCA is not yet well documented and we believe that MCA may actually be underdiagnosed by practicing pathologists.
Herein we report 8 patients in which we microscopically detected lesions with histological and immunohistochemical features reminiscent of MCA (CD34 and CD68 immunostainings were systematically performed). Interestingly, in most of these cases (n = 7), MCA developed within a cutaneous neoplastic or reactional process, whereas in the remaining case (patient 1, Table 1), it presented as erythematous papules on the leg, as classically described, allowing diagnosis of MCA.2 As shown in Table 1, we identified MCA-like lesions at the periphery of nonmelanoma skin cancers (basal-cell carcinoma and squamous-cell carcinoma) in 2 cases (Fig. 1A-B), and surrounding a xanthelasma in another. In the 3 remaining cases, MCA arose in conjunction with various reactive conditions involving the skin. In one 21-year-old woman with hidradenitis suppurativa, it actually developed on the axilla, nearby chronic inflammatory lesions of the dermis, whereas in another 84-year-old woman, it was found within chronic radiation dermatitis (Fig. 1C-D), on a breast previously treated by tumor resection followed by chemotherapy and radiation therapy. In patient 7, MCA-like lesions were found on the knee, overlying a bone prosthesis placed because of degenerative joint disease. Although most of these cases do not fit within the classical clinical presentation of MCA, we believe they are closely related, if not similar lesions, because they all showed the prototypical morphologic and phenotypic features of this lesion. Our cases featured all histologic criteria of MCA, but whether they are “real” MCA or just reactive processes mimicking the microscopic aspects of MCA cannot be investigated, in the absence of a specific marker of MCA's cells. We may, however, speculate that the clinical spectrum of MCA could be broader than usually described in the literature and may encompass “idiopathic” and reactive variants. It is conceivable that in patients 2-8 from our series, MCA-like lesions rather represented a reactive process to chronic injury, that is, cancer with stroma inflammatory reaction, chronic inflammation (hidradenitis suppurativa), chronic radiation dermatitis, and scarring, than a neoplastic process per se. In agreement with our findings, a case of MCA associated with mycosis fungoides has been reported.5 Interestingly, in the last patient reported here (patient 8), MCA was diagnosed on the leg and medical history revealed that she presented 15 months ago with an eruption, showing histologically a dermal lymphocytic capillaritis. We therefore may ask whether MCA may be caused, even partly or initially, by vascular injury. All this, however, remains speculative, all the more that classical MCA develop without prior history of skin tumor or reactive condition, as far as we know.
Julien Calderaro, MDLuc Rethers, MDNicolas Ortonne, MD, PhD
Department of Pathology, Henri Mondor Hospital, Creteil, France
1. Smith LP, Wilson-Jones E. Multinucleate cell angiohistiocytoma: a new entity. Br J Dermatol
2. Jones WE, Cerio R, Smith NP. Multinucleate cell angiohistiocytoma: an acquired vascular anomaly to be distinguished from Kaposi's sarcoma. Br J Dermatol
3. Rawal YB, Anderson KM, Rawal SY. Multinucleate cell angiohistiocytoma: an uncommon mucosal tumour. Clin Exp
4. Puig L, Fernández-Figueras MT, Bielsa I, et al. Multinucleate cell angiohistiocytoma: a fibrohistiocytic proliferation with increased mast cell numbers and vascular hyperplasia. J Cutan Pathol
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5. Bader RS, Telang GH, Vonderheid EC. Multinucleate-cell angiohistiocytoma occurring in a patient with mycosis fungoides. Cutis