The patient was a young man in his early thirties who initially presented with a single nodular lesion on his left shoulder when traveling to a metropolitan area in Southeast Asia in November 2014. The lesion was hemorrhagic and ulcerated. An attempt was made to ablate the lesion using a laser procedure; however, it subsequently recurred in January 2015. Shortly thereafter, additional smaller lesions developed in the same area (Figure 1). Intralesional steroids and minocycline were ineffective. He felt that burning the lesions limited their spread and bleeding.
The patient’s past medical history was remarkable for hypothyroidism and also low testosterone. The patient was on testosterone supplement and daily men’s vitamins. The patient engaged in contact sports and was an avid avocational wrestler. The patient denied experiencing any constitutional symptoms prior to or since developing the eruption. Three biopsies were taken from the affected areas including the left scapula and forearm.
Light Microscopic Findings
The biopsy in specimen A showed a well-circumscribed, superficially disposed nodular distortion of the dermis by closely apposed vessels and singly disposed cells amidst a somewhat fibrotic dermis (Figure 2A).1,2 The vessels were lined by atypical plump endothelial cells (Figure 2B). The endothelia were prominent with conspicuous nucleolation and some degree of nuclear hyperchromasia. In addition, similar cells were found in a single cell array amidst the well-formed vessels (Figure 2C). Human herpesvirus 8 (HHV8), Epstein-Barr virus, and cytomegalovirus preparations were negative. A Warthin-Starry preparation to assess for possible parasitization of the abnormal endothelial cells by Bartonella bacilliformis and other species3 was negative.
The biopsy in specimen B demonstrated a very atypical vascular proliferation with foci of glomeruloid neovascularization reminiscent of the pattern seen in the A specimen, but there was an additional significant pattern of infiltrative vascular proliferation (Figure 2D). A number of bizarre cells scaffolding in a single cell fashion along collagen and elastic fibers were observed defining a pattern reminiscent of an angiosarcoma given the extent of cellular atypia and the distinct infiltrative growth pattern along the collagen and elastic fibers. The endothelial cells were remarkable for their large size and abundant amphophilic cytoplasm and bizarre nuclear features. The cytoplasm ranged in quality from being eosinophilic to amphophilic in quality. Several of the very atypical cells exhibited large cytoplasmic vacuoles. The atypical vascular channels and singly disposed cells without any vasoformative tendency were highlighted by clusters of differentiation (CD) 34. The cytomegalovirus, HHV8, and Epstein-Barr virus stains (LMP1) were negative. Immunohistochemical and molecular assays were negative for all Bartonella species examined, including Bartonella quintana, Bartonella henselae, and Bartonella vinsonii.
The case represents an atypical cutaneous eruptive angiomatous process occurring in a healthy young man. The eruption was of sudden onset without any obvious inciting trigger. It was regionally confined and was histomorphologically characterized by an atypical vascular proliferation lined by abnormal enlarged endothelial cells, which also appeared to assume a nonvasoformative single-cell growth pattern in the dermis. The cells had a distinctly epithelioid appearance manifesting nuclear hyperchromasia and nuclear enlargement, and cytoplasms were abundant and amphophilic to eosinophilic and somewhat vacuolated in quality as well. While the proliferation was very abnormal cytomorphologically and architecturally, the overall cutaneous presentation was not consistent with an epithelioid angiosarcoma, which has been reported to arise in association with reactive angioendotheliomatosis.4,5 The differential diagnosis encompassed multicentric cutaneous angiosarcomatous mimics. There are four main diagnostic considerations, and each will be considered separately.
The first consideration is Kaposi sarcoma. However, the negative HHV8 stain would not be consistent with this diagnosis given the relatively ubiquitous association of HHV8 with Kaposi sarcoma.6
The next is infective angioendotheliomatosis attributable to a Bartonella species. Verruga peruana, a cutaneous manifestation of B bacilliformis, is characterized by an eruption of red to purple papules or nodules on the face and extremities. Histologically, these lesions show proliferation of endothelial cells with cytologic atypia that can range in morphology from an epithelioid hemangioma-like appearance to more solid and spindled appearance that can mimic sarcomas.7 While certain aspects of the histopathology in this case are reminiscent of verruga peruana, the clinical features and basic epidemiology are not consistent with the diagnosis. First, B bacilliformis has exclusively been reported in the South American countries of Colombia, Ecuador, and Peru in the Andes mountains.8,9 This patient traveled to Southeast Asia before the lesion manifested, where B bacilliformis has not been reported.10,11 Next, verruga peruana can be preceded by Oroya fever, which causes symptoms of fever, headaches, and muscle aches.12 This patient denied experiencing any of such symptoms. Bacillary angiomatosis, a related infective angioendotheliomatosis syndrome caused by B henselae that is most often associated with HIV/AIDS, was also considered. Bacillary angiomatosis is characterized by vascular proliferation with lobules composed of rounded edematous vessels lined by protuberant endothelial cells and neutrophilic clusters. Many organisms parasitizing pericytes are typically seen on Warthin-Starry stain, unlike in this case.13 One might further consider a species of Bartonella, distinct from the three most common, that have been found in mammalian reservoirs in Southeast Asia.10,11 Nevertheless, the molecular and immunohistochemical investigation were negative.