Kaposi sarcoma (KS) is a rare, low-grade malignant tumour induced by the herpesvirus 8 (HHV-8). The condition primarily affects the skin although other organs can be involved. Distinct subtypes of the condition have been identified. Typically, macular purpuric lesions appear on the extremities, particularly the feet. The authors present a case of KS identified in an elderly male attending a podiatry clinic. He was subsequently treated with radiotherapy and has a good prognosis. Podiatrists should be aware of this striking but rare condition which initially may present as unusual multiple lesions on the feet.
An 86-year-old man presented for a podiatry appointment for treatment of his recurrent fungal skin and toenail infection. At this appointment, his podiatrist noted several violaceous, purpuric macular lesions present on the soles, along the lateral borders of the feet extending onto the lower shin area (FIGS). Medically, he had a history of vascular disease, previously suffering a heart attack and developing subsequent heart failure. He had had a coronary bypass with stents and a heart valve replacement. He also had carotid stenosis. His current medication was Aspirin, Atorvastatin, Bisoprolol, Candesartan, Clopidogrel, Furosemide and Omeprazole. He had also used topical antifungal creams periodically to manage his tinea pedis. Socially, he was a non-smoker, taking only occasional alcohol. In conversations with the podiatrist, he openly described himself as being homosexual.
The podiatrist initially suspected the purpura may be the result of his antiplatelet medication causing small areas of bleeding into the skin but advised the patient to seek an opinion from his general practitioner (GP). At his next appointment with the podiatrist, the patient had not yet consulted his GP. New lesions had appeared and several of the existing lesions had become nodular. Further discussions with the patie
nt at his appointment and by telephone about the progression of the lesions had persuaded him to consult his GP, as the clinical picture strongly suggested KS.
Following an assessment by the GP, he concurred with the podiatrist’s thoughts and made an urgent referral to the local Dermatology Department. The patient had biopsies performed which confirmed the diagnosis of KS. He underwent CT’s of his thorax, abdomen and pelvis and followed on with an ultrasound scan of his abdomen. An HIV test was negative and was subsequently repeated and again returned a negative result. The CT scan revealed lesions on his kidneys, spleen and lungs. Subsequent contrast-enhanced ultrasound concluded that the lesions on the kidney and spleen were not issues of concern he was awaiting further scans on his lungs. He underwent radiotherapy to treat his skin lesions and returned to his podiatrist. Visible improvements were noted with regressing lesions becoming flattened and fading (Post-op images are given below).
Kaposi Sarcoma is a rare, virally induced tumour. The term “sarcoma” is now known to be a misnomer as it is not a tumour of mesenchymal origin but one of multicentric vascular hyperplasia. It affects blood vessels and can develop on soft tissue in multiple areas, simultaneously. Lesions tend to be asymptomatic, pink to dark blue or purple patches and papules, coalescing to form larger lesions of several centimetres. Rapid progression to multiple ulcerative plaques and nodules is not uncommon. Lower limb swelling may occur in certain forms of KS. Mucosal lesions are also frequently observed. Tumours typically appear on the feet, legs, ears or nose face or lymph nodes, but may develop in the digestive tract, liver, spleen and lungs in severe cases causing abdominal pain, weight loss or internal bleeding.
Diagnosis is confirmed by biopsy but initially, solitary lesions may mimic other conditions such as malignant melanoma, glomus tumour, angioma, purpura, histiocytoma and sarcoid. The four recognised groups have been described by Bishop and Lynch . Classic Kaposi sarcoma has a male: female ratio of 17:1 and occurs primarily in patients over 50 years old of Eastern European and Mediterranean descent. These patients are at greater risk for secondary malignancies. The prevalence mirrors the distribution of HHV-8 throughout the world. Within the United States, the incidence has been stable around 1:100,000 since 1997. These lesions are usually indolent and rarely aggressive and disseminated.
Endemic Kaposi sarcoma has an unusual predilection for the paediatric population and mirrors HHV-8 seropositivity. The rates of seropositivity in paediatric patients vary extensively throughout Africa, from a low of 2% in Eritrea to almost 100% in the Central African Republic. Following the HIV epidemic in Africa, the ratio of men to women with Kaposi sarcoma has fallen from 7:1 to 2:1. Endemic Kaposi sarcoma is now the most common cancer in men and the second most common cancer in women in Uganda and Zimbabwe. These lesions can be indolent or locally invasive but can have visceral involvement especially in children where it can be aggressive.
AIDS-related Kaposi sarcoma is the second most common tumour in HIV patients and is an AIDs-defining illness. Up to 30% of HIV patients not taking high-activity antiretroviral therapy (HAART) will develop Kaposi sarcoma. HIV-positive male homosexuals have a 5- to 10-fold increased risk of Kaposi sarcoma. Visceral involvement is not uncommon and can be aggressive.
Iatrogenic Kaposi sarcoma has a male: female ratio of 3:1. Over 5% of transplant patients who develop a de novo malignancy will develop Kaposi sarcoma, a 400- to 500-fold increased risk over the general population. Patients with bone marrow or peripheral blood stem cell transplants have much lower risks of developing Kaposi sarcoma compared to solid organ transplant patients. Tumours typically appear as painless, purplish spots. These lesions usually remain localised but can involve organs. The four main types are summarised in table 1 below .
Recently a possible further fifth group has been recognised . A meta-analysis of examining 93 studies and 58 357 patients identified men who have sex with men (MSM) and who are HIV seronegative with no identifiable immunodeficiency as a group with a strong risk for developing KS. The authors suggest that sexual transmission of the HHV8 virus is likely amongst this group . The patient presented in this case did not fit into any of the recognised categories and tested negative twice for HIV so consequently may be categorised into this proposed fifth group.
Early diagnosis is important to prevent metastasis. The classic form was first described in 1872 by Moritz Kaposi it was not until a century later when it became widely recognised, then, as an early indicator of a new disease called AIDS. Only in 1994 was the HHV-8 identified as the causative agent of KS . However, acquiring the viral infection is not sufficient alone to develop KS and typically a background of immune suppression is required to induce the development of the condition although hypoxia, oxidative stress, viral coinfection, epigenetic modification, and hyperglycaemia have also been shown to induce tumorigenesis . The background seropositive rates of HHV-8 infection in North America is very low but high in sub-Saharan Africa where KS is endemic it can range between 50-100% .
Management of skin lesions, in part, is informed by the presenting sub-type of KS. Limited localised disease may be managed by localised therapies, whereas systemic therapies are reserved for more widespread disease. Skin involvement of Kaposi sarcoma is treated by local excision, liquid nitrogen, intralesional chemotherapy. KS is highly radiosensitive and is used with large areas of involvement.
Patients with HIV-related Kaposi sarcoma respond well to highly active antiretroviral therapy (HAART), which can cause regression or complete treatment of their sarcoma. In patients with severe Kaposi sarcoma, HAART is combined with chemotherapy. Iatrogenic Kaposi sarcoma is managed by careful balance between reducing the immune-suppression without inducing transplant rejection.
Kaposi sarcoma is a rare skin disease that may involve other organs. This case presents an unusual form occurring in an HIV-negative male which may represent a new group of patients with the disease. The early recognition of the unusual skin lesions, typically on the foot should alert the podiatrist to make an immediate referral for diagnosis and treatment.
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