Discussion
While oral (59.1%) and craniofacial (43.9%) involvement is common in HIV-positives(1), Kaposi sarcoma of the head and neck is rare (approximately <5 % of the KS cases) in the HIV-negative individuals. 6 The most common presentation of KS in HIV-negatives is multiple bilateral lesions of the lower extremities.7 Among the head and neck KS, the incidence of auricular involvement is much lower, so it should be considered a distinct manifestation. The presence of a recurrent, auricular KS with an atypical presentation in a young immunocompetent individual is a very rare finding.
In this article, we presented a case of recurrent KS on the ear with a literature review on ear KS cases (Table 1). 5, 6, 8-27 The literature review disclosed 24 cases since the year 1941 until 2020, highlighting the rarity of this presentation. Sixteen males and seven females aged 3-85 years (median, 62 years; mean, 57.4 years) were retrieved. Of these 24 cases of ear skin KS, 2 cases were HIV-positive24, 27, 13 cases were HIV-negative6, 16-23, 25, 26 and others were unknown. Among these, 4 cases had visceral involvement including lymph node, bone, urethra, stomach, colon, liver and spleen and the rest were limited to the skin including Just limited to the auricle (n=11), ear and mucosal sites (n=4), ear and extremities (n=9), ear and other sites in the head and neck region (chin, eyelid) (n=3). Among the 13 HIV-negatives, 5 cases had some degrees of immunosuppression (1 case kidney transplantation25, 1 case Congenital immunodeficiency25, 1 case receiving systemic corticosteroid23, 1 case non-Hodgkin lymphoma21 and the last a case of severe lymphocytopenia17. While excision was the most common treatment option, other modalities were antiretroviral medications for HIV-positives, radiotherapy and chemotherapy with liposomal doxorubicin, bleomycin, vincristine and IFN-alpha for more widespread disease. Among 17 cases that their follow up were available, ranging from 15 months to 17 years, the majority of them were free of disease after the initial treatment (n=12), 3 cases had recurrent lesions, 1 case was alive with disease and 1 died with disease because of uremia. While KS in HIV-negative patients has an indolent coarse, our case was highly recurrent, despite total excision with free margins, it has recurred twice in five years and after that, a new lesion on the foot appeared. So the recurrence rate of the KS in the ear needs to be further studied.
While KS pathogenesis is multifactorial and both genetic and environment are responsible, Human Herpes Virus 8 (HHV8) is the main causal factor in the development of KS in all variants irrespective of the clinicopathological setting of the disease. 4, 28 HHV8 contributes to cell growth, signaling apoptosis, angiogenesis, and immunomodulation. It produces some proteins that inhibit host adaptive and innate immunity. 1, 4 While the increased risk of KS in HIV-positives and iatrogenically immunosuppressed cases is well understood, the occurrence in immunologically competent individuals remains largely unelucidated. 7 Agaimy A et al hypothesized that maybe impaired local immunosurveillance and pro-inflammatory cytokines release is the causative factor.6 Although the exact reason why the ear is a predilection site in HIV negative patients who develop KS in head and neck region is not clear Francés RL et al proposed that in addition to some factors such as trauma and infection in acral sites, insufficient vascularization makes it difficult for immune system to access.22
Due to the rarity of head and neck, KS, especially in HIV- negative patients, unusual presentations of KS may be challenging if not considered in the differential diagnosis. The occurrence of KS in atypical sites like ear leads to unrecognition and misdiagnosis. The possibility of occult HIV infection should be considered beside. They may be misdiagnosed as other spindle cell tumors pathologically or other vascular lesions such as ALHE clinically. HHV8 immunohistochemistry was positive in 95 % of KS lesions irrespective of HIV positivity4, so it is a good marker to detect KS.
In summary, we presented a case of recurrent ear KS in a young HIV-negative and otherwise healthy individual with a review of the literature on 24 cases of ear KS from 1941 to 2020 implicating ear as a predilection site for head and neck KS in HIV-negative patients, therefore, we highly suggest to consider KS as a differential diagnosis for lesions on ears.
Author 1: has made substantial contributions to conception and design, acquisition of data, analysis and interpretation of data, drafting the manuscript and revising it critically, given final approval of the version to be published. Author 2: has made substantial contributions to conception and design, acquisition of data, analysis and interpretation of data, drafting the manuscript and revising it critically. Author 3: has made substantial contributions to conception and design, drafting the manuscript and revising it critically, Author 4: has made substantial contributions to conception and design, acquisition of data, analysis and interpretation of data, drafting the manuscript and revising it critically.