Tuberculosis verrucosa cutis complicating tropical elephantiasis

To the Editor

A 55-year- old farmer came with swelling of the right leg for 3 years, associated with a verru-cous growth of 1 year duration. Initially, the patient had noticed intermittent swelling of the right leg and foot along with fever, chills, rigor and painful inguinal swelling. Gradually, the swelling of the right leg be-came persistent, but without any further bouts of fever. He gave history of repeated episodes of trauma to the leg followed by pain and foul smelling dis-charge which used to subside with antibiotics. For the past 1 year, he had noticed multiple verrucous growths on the swollen leg which had gradually coalesced to form a painless, large warty lesion. There was no personal or family history of pulmonary tu-berculosis.

He was a moderately nour-ished individual with diffuse, non pitting oedema of the right leg and foot with thickening of the skin and fissuring of the sole. A large 25 x 20 cm verrucous plaque was observed on the, anterior and medial aspect of the right leg [Figure - 1]. The plaque was non tender, firm in con-sistency with some soft, shiny areas in the centre. The inguinal Iymphnodes were moderately enlarged bilaterally. They were discrete, firm and non tender. His systemic examination was unremarkable.

The haemogram revealed a raised erythro-cyte sedimentation rate (30 mm in the first hour) and eosinophil count of 5%. Peripheral smear for microfilaria was negative. The Mantoux test was strongly positive (20x 15 mm). X-ray of the chest did not show any abnormality while X-ray of the right leg showed soft tissue swelling with no bony changes. Filarial serology by indirect haemagglutination was positive in significant titre (1:128). A skin biopsy from the verrucous plaque showed marked hyperkerato-sis of the epidermis with pseudoepitheliomatous hy-perplasia. The upper and mid portion of the dermis showed intense, mixed infiltrate of iymphocytes, epi-thelioid cells and a few Langhans giant cells. Fite′s stain for acid fast bacilli (AFB) was negative. These features were consistent with tuberculosis verrucosa cutis. AFB and fungal culture from the tissue speci-men were, however, negative.

A diagnosis of filarial elephantiasis with tu-berculosis verrucosa cutis was made. The patient was treated with diethyl carbamazine (DEC) tablets, 100 mg three times daily for 21 days. Also, he was put on antituberculous therapy - rifampicin, isoniazid, pyrazinamide and ethambutol for 2 months, followed by the former 2 drugs alone for 4 months. At 3 months, the verrucous plaque had subsided completely, though swelling of the right leg was still persistent.

Cutaneous tuberculosis, perceived to form a continuous spectrum, with lupus vulgaris and tuber-culosis verrucosa cutis (TBVC) at one end and scrofu-loderma and tuberculosis cutis orificialis at the other, corresponds to a declining cell mediated immunity across the spectrum[1],[2] TBVC, a verrucous form of cutaneous tuberculosis results from innoculation of tubercle bacilli into the skin of a previously infected patient with moderate to high degree of immunity,[1] Cell mediated immunity (CMI) which plays a para-mount role in cutaneous tuberculosis, is reduced in filarial elephantiasis[3] and the occurrence of TBVCQ with a strongly positive Mantoux test in our patient sug-gests that the modulation of CMI is specific for each chronic infection. Earlier, TBVC complicating n trophic ulcer in a lepromin negative patient has been re-ported from our institute.[4]

Lymphatic filariasis which begins as filarial fever and lymphangitis leading on to lymph stagna-tion and elephantiasis over a period of 10 to 15 years after infection,is quite common in South India.[3],[5] The surface of the skin can become rugose and warty due to elephantiasis per se.s The verrucous lesion in our patient responded to antituberculous therapy. Also, it needs to be differentiated from malignant tumour and deep fungal infection. These possibili-ties were ruled out by skin biopsy and fungal culture examination. Factors such as (i) lymphatic stasis lead-ing to luxurious growth of fibroblasts, (ii) impairment of blood supply, (iii) vulnerability to trauma, (iv) ac-cumulation of sebaceous material and dirt in the in-folded skin of the affected limb, provide the ideal environment for known complications like ulceration, secondary infection, suppuration and gangrene.s In our case, tubercle bacilli were innoculated as sec-ondary invaders resulting in TBVC, yet another complication of tropical elephantiasis, not reported so far in the literature.