Acroangiodermatitis (Pseudo-Kaposi sarcoma).

Acroangiodermatitis or Pseudo-Kaposi sarcoma is a rare angioproliferative entity, related to chronic venous insufficiency or certain other vascular anomalies. It is often associated with chronic venous insufficiency, arteriovenous malformation of the legs, chronic renal failure treated with dialysis, paralyzed legs and amputation stumps. We hereby describe a case of 45 year old female presenting with pitting pedal edema, multiple ulcers over bilateral lower limbs with irregular margins with erythema and hyperpigmentation of the surrounding skin. Color Doppler study of bilateral lower limbs was normal. Histopathological examination from one of the lesions showed hyperplastic epidermis, proliferation of capillaries in dermis, hemosiderin deposits and lymphocytic infiltrate. These features thus confirmed the diagnosis of Acroangiodermatitis.

INTRODUCTION

Acroangiodermatitis, also known as Pseudo-Kaposi sarcoma is a reactive angiodysplasia of cutaneous blood vessels often seen in association with venous insufficiency or with certain vascular anomalies.[1] It is a benign condition which clinically presents as violaceous macules, indurated plaques or nodules usually bilaterally on the extensor surfaces of lower extremities. The term acroangiodermatitis of Mali was introduced for the first time by Mali et al. in 1965.[2] Although benign, it must be differentiated from malignant conditions like Kaposi's sarcoma, especially in the present HIV era and therefore, histopathological examination is a must for its diagnosis and differentiation.

CASE REPORT

A Forty five-year-old previously healthy female presented with complaints of swelling and pain in bilateral feet for eight years and history of recurrent episodes of multiple nodules over bilateral legs and feet, which burst to form ulcers for a period of seven years. There was no history of any preceding drug intake. There was no history of similar complaints in family members and no history suggestive of systemic illness. On examination, there was pitting pedal edema, multiple ulcers over bilateral lower limbs (one over medial malleolus of right foot and two over lateral aspect of the left foot) measuring about 1-2 cm in size, slightly tender, irregular margins, sloping edges, floor of the ulcers were covered with slough with erythema and hyperpigmentation of the surrounding skin. Multiple scars of previously healed wounds were present [Figure 1a and b]. There was no palpable thrill or bruit, no clinical evidence of varicose veins and no significant lymphadenopathy. All the peripheral pulsations were well felt. Systemic examination was within normal limits. Routine investigations including complete blood counts, liver and renal function tests, urinalysis, chest radiographs were within normal limits. Enzyme linked immunosorbent assay (ELISA) for HIV 1 and 2 was non reactive. The result of Mantoux test was negative. Bleeding time, clotting time and prothrombin time were within normal limits. Color Doppler study of bilateral lower limbs was within normal limits. Based on the history and investigations, differential diagnosis of chromoblastomycosis, mycetoma, vasculitis and erythema induratum was kept. Histopathological examination of a biopsy sample from the edge of the lesion showed hyperplastic epidermis with an increased number of thick walled capillaries in the papillary, mid and reticular dermis. Moderate amount of hemosiderin deposits were seen around these vessels with perivascular lymphocytic infiltrate and mucin [Figure 2]. Based on the history, examination and histopathology findings, a final diagnosis of Acroangiodermatitis of Mali was made.

Figure 1a

Multiple irregular ulcers with surrounding hyperpigmentation and multiple scars present over lateral aspect of left foot and lower leg

Figure 1b

Single superficial ulcer over medial malleolus of right foot in healing stage with surrounding hyperpigmentation

Figure 2

Proliferation of thick walled capillaries in dermis with moderate amount of hemosiderin deposits around the vessels alongwith perivascular lymphocytic infiltrate (H and E, ×100)

DISCUSSION

Acroangiodermatitis is an uncommon angioproliferative entity, related to chronic venous insufficiency, arteriovenous fistulae, paralysed limbs, amputation stumps, vascular syndromes and conditions associated with thrombosis. It is a proliferation of pre-existing vasculature seen in venous hypertension, arteriovenous malformation, or acquired iatrogenic arteriovenous (AV) fistula.[1] Most of the previously reported cases were associated with venous insufficiency, but few cases of spontaneous presentation have also been reported.[3] It is rarely reported in hereditary coagulation defects, i.e., carrier of the thrombophilic 20210A mutation in the prothrombin gene and homozygous activated protein C resistance.[4] Various variants of acroangiodermatitis have been described including Stewart-Bluefarb syndrome (congenital arteriovenous malformation of the lower leg with multiple AV shunts), Mali type (an exaggerated stasis dermatitis seen in elderly patients, which is usually bilateral associated with chronic venous insufficiency), Acroangiodermatitis in first pregnancy presenting as gravity purpura (Dermite ocre of Favre) on lower legs over site of venous varicosities, Angiodermatitis occurring after placement of the arteriovenous shunt for hemodialysis in chronic renal failure.[15]

Rashkovsky et al. described acroangiodermatitis as a condition that occurs in five different clinical conditions, i.e., chronic venous insuffciency and arteriovenous malformation of the legs, chronic renal failure treated with dialysis, paralyzed legs and amputation stumps.[6] Chronic pressure changes with the vessel proliferation in the upper and mid-dermis and extravasation of red blood cells produce a combination of purplish papules and plaques on the edematous skin.[7] It presents clinically as acroangiodermatitis characterized by multiple papules, nodules and plaques, sharply defined reddish-brown, sometimes in bizarre configurations, generally localized on the dorsal aspect of the foot and the lower aspect of the shin, usually associated with edema. In cases of chronic venous insuffciency, lesions are often bilateral, while in other disorders, there is an underlying clinical defect (signs of vascular or neurologic problem) and the lesions tend to be unilateral.[7] Histopathological examination shows proliferation of endothelial cells, newly-formed vessels with thick walls, often in a lobular pattern and surrounded by pericytes in the dermis. Extravasation of red blood cells, hemosiderin pigment deposition, dermal fibrosis, small thrombi in the lumen and superficial perivascular infiltrate of lymphocytes, histiocytes and occasional plasma cells are also found and may resemble Kaposi's sarcoma. This, however, has vascular slits, proliferation of fusiform cells and atypical cells, and the vascular hyperplasia is independent of pre-existing vasculature.[89] Immunohistochemical staining with Cluster of differentiation (CD34) antiserum helps to distinguish between acroangiodermatitis and Kaposi's sarcoma, because in the former, an absence of perivascular CD34 is noted, unlike in the latter (CD34 staining on the endothelial cells as well as the perivascular spindle cells).[10]

Treatment of this condition has not been discussed in detail in the previous literature available, mainstay of treatment being the correction of the underlying pathology. The use of compression bandages, stockings or pumps helps in relieving symptoms in cases of underlying circulatory disturbances. Various medical modalities of therapy have been tried with favorable results, but options are limited. Oral erythromycin 500 mg four times a day or dapsone 50 mg twice a day for 3 months in combination with compression therapy has been tried with good results.[4] Topical therapy with local corticosteroid preparations is often useful.[7] Underlying vascular pathology like arterio-venous malformations should be surgically managed with elimination of the shunts and embolization for small fistulae.[15]

The patient was prescribed topical corticosteroids and oral dapsone 100 mg daily and showed a response in the form of resolution of existing lesions with persisting hyperpigmentation and atrophic scars after 6 weeks of follow-up. The authors thus would like to emphasize that diagnosis of Pseudo-Kaposi's sarcoma must be considered in such a presentation and histopathology should be considered as the gold standard in differentiating it from aggressive malignant conditions like Kaposi's sarcoma.