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Angiolymphoid Hyperplasia with Eosinophilia
(Epithelioid hemangioma with lymphoid stroma: a lesion exhibiting distinctive, high endothelial cells of post-capillary venule-type)
Angiolymphoid hyperplasia with eosinophilia is a poorly understood disorder. Without regard for cell marker studies, the cytologic character of the endothelial cells in this disorder
might be cited as a feature strongly in favor of a endothelial neoplasm, rather than a lymphoid lesion with a reactive hyperplasia of vessels. In this disorder, there is a spectrum of atypical changes from one
lesion to the next, and even from one vessel of a lesion to the next vessel. The wide range of degrees of atypia in the endothelial component is evidence strongly in favor of the endothelial nature of the
process.The lymphoid tissue and the associated inflammatory cells, which include plasma cells, histiocytes, and eosinophils, are not characterized by significant variations in degree of cytologic atypia. In
addition, some examples are relatively free of inflammatory cells; they can be easily accommodated in the category of epithelioid hemangioma, or atypical epithelioid hemangioma.
Classically, the lesions have organoid qualities with lobular arrays of vessels. Lesions, which are well-circumscribed (particularly subcutaneous examples), usually show zonal
patterns with the greatest immaturity of vessels in the vicinity of a muscular feeder vessel, and with maturation at the periphery of the lesion. In this approach, immaturity is manifested in patterns in which the
endothelial cells are plump and epithelioid. The greater the degree of immaturity, the greater the representation of solid cords of these plump endothelial cells. In the most immature zones, some of the cells will
show distinct cytoplasmic vacuoles (such vacuoles identify the respective cells, and their immediate neighbors [i.e., cytologically similar cells, but lacking cytoplasmic vacuoles] as “angioblasts”). In
slightly more distant zones (away from the feeder vessel), cytoplasmic vesicles of the vacuolated endothelial cells coalesce to form channels; the lining cells remain plump and have plump nuclei which commonly are
cleaved (they have “histiocytoid” qualities). They bulge into the lumens of the newly channelized vessels. The relationships between the vessels and the lymphoid infiltrates become evident at the periphery of these
lesions. In these areas, the vessels are fewer in number, loosely spaced, and have the characteristics of post-capillary venules. Clearly, the cytologic qualities, of the more mature endothelial cells, serve to
identify the respective vessels as having the features of post-capillary venules; such vessels are structured to favor the egress of cells from lumens into stroma (and vice versa). Lymphoid cells and other
inflammatory cells are recruited from within the distinctive vessels to populate the stroma. The process might be characterized as a distorted recapitulation of phenomena which are operative in the formation of
lymph nodes in developing fetuses. Similar phenomena are operative in sites of inflammation.
Atypia, in the endothelial component of a lesion of angiolymphoid hyperplasia with eosinophilia, is of questionable significance, if the organoid patterns are preserved. Lymphoid
infiltrates also favor a benign process. At least one example with organoid qualities and lymphoid infiltrates has been associated with nodal involvement, but on follow-up there was no evidence of progressive
disease The patient was pregnant at the time of diagnosis and the lymph node biopsy. (here, a young Nia Terezaki comes to mind).
Szaniawski WK, et al: Epithelioid angiomatosis in patients with AIDS. J Am Acad Dermatol 1990;23: 41-8.
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