Eruptive Pseudoangiomatosis: clinicopathologic report of 20 adult cases and literature review

Background: Eruptive pseudoangiomatosis (EPA) is a distinctive, self-limiting, spontaneously resolving exanthem of unknown aetiology. It is characterised by an eruption of erythematous, angioma-like papules, which are a few millimetres in diameter and surrounded by a white halo. We performed this study to evaluate the epidemiology, clinical and histological presentation, aetiology, and differential diagnoses of this unique exanthem and compare our findings to those of the literature review. Methods: 20 inpatients diagnosed with EPA during an outbreak at Policlinico San Matteo hospital, Italy in 2013 were included in a retrospective study. Diagnoses were based on clinical and histological findings and supplemented by serological investigations. Patient age, gender, month of occurrence, lesion location, comorbidities, disease duration, laboratory and serological findings were analysed. A comprehensive literature review was conducted on Pubmed using the term “eruptive pseudoangiomatosis”. Results: 15 women and 5 men were identified within the age range 37-88 years, with the mean age at onset being 66.7 years. All of the cases observed occurred in the months of June-September. All patients developed the typical, erythematous, angioma-like papules measuring a few millimetres in diameter and surrounded by hypochromic halos. Extremities, especially the upper limbs, were the most commonly affected sites. None of the patients experienced prodromal or any associated systemic symptoms. Histology revealed blood vessel dilatation mainly in the upper dermis and plump endothelial cells with prominent nuclei in all cases. Routine laboratory tests revealed leucocytosis, especially neutrophilia, in 6 cases and anemia in 8 cases. One patient was positive for circulating HHSV7 DNA, while another was positive for IgG and IgM against PVB19 as well as circulating PVB19 DNA. One patient tested positive for Proteus mirabilis on haemoculture. All patients experienced a spontaneous resolution of the lesions within 7-20 days. None of the patients were treated with any drug or topical cream, and there were no recurrences observed. Conclusion: The clinical picture of EPA is constant and sufficient for diagnosis when associated with its histopathological pattern. EPA is probably induced by a viral infection even if it is still unclear whether viruses play a direct role in determining cutaneous lesions or it could be considered a paraviral eruption. According to literature and our observations, cutaneous lesions could appear both in case of primary infection or viral reactivation. In particular, we herein report an association with parvovirus B19 infection that, to the best of our knowledge, has never been reported before.

Pseudoangiomatosi errutiva: rapporto clinicopatologico di 20 casi adulti e revisione della letteratura