Chronic osteomyelitis of humerus presenting as scrofuloderma.

Scrofuloderma is a common type of cutaneous tuberculosis usually manifests over an infected lymphnode, bone or joint that breaks down to form an undermined ulcer leading to discharging sinuses. We present a case of a 22 year old woman with diffuse swelling of right arm with overlying nodulo ulcerative skin lesions associated with seropurulent discharge. Routine investigations were normal and X-Ray of the right humerus showed the features of chronic osteomyelitis. Smears of the discharge for bacteria, fungi and acid fast bacilli were negative, but culture of skin biopsy showed Mycobacterium tuberculosis which was confirmed by PCR. Histopathology of skin biopsy showed epithelioid granulomatous inflammation suggestive of tuberculosis. After treating the patient with antitubercular therapy complete regression of the lesions occurred.

What was known?

Cutaneous tuberculosis with involvement of underlying bones and joint were reported previously. Most commonly involved sites are vertebrae followed by hip.

Introduction

Cutaneous tuberculosis has a worldwide distribution.[1] It is a form of extrapulmonary tuberculosis occuring in 1% of all tuberculosis cases.[2] Many types of cutaneous tuberculosis like lupus vulgaris, scrofuloderma, tuberculosis verrucosa cutis, tuberculous gumma, orificial tuberculosis etc., are described.[34] Scrofuloderma is also known as “Tuberculosis colli quativa cutis” resulting from direct extension of underlying tuberculous foci such as lymphnode, bone or joint to the overlying skin.[5]

Tuberculosis of bones and joints accounts for 1-3% of patients with tuberculosis.[6] Most frequently involved sites are vertebrae followed by hip.[7] Tuberculosis of other areas of bone is less common and detected at a much more advanced stage, of which tuberculosis of the humerus is less often reported. We present a case of tuberculous osteomyelitis of humerus with multiple skin ulcers which was successfully treated with antitubercular therapy.

Case Report

A 22 year old female presented with discharging sinuses and swelling over the right arm of 18 months duration. She received courses of antibiotics at a local clinic. The nodulo-ulcerative discharging sinuses were initially small sized but failed to heal and continued to increase in size. On local examination multiple crater like ulcers with few papulo-pustular lesions on the dorso-lateral aspect of the lower two-third of right arm were seen [Figure 1]. The ulcer had indurated margin surrounded by a zone of hyperpigmentation with mild seropurulent discharge and crust formation at the base of the ulcer [Figrue 2]. Features of eczematization were seen on the surrounding margins of the ulcer. There was local rise of temperature on the overlying skin. No regional lymphadenopathy was detected. Systemic examination did not reveal any abnormalities. There was no history of recent loss of weight and night sweats. There was no history of trauma or immune suppressive therapy. But the family history revealed a treated case of pulmonary tuberculosis in one of the family members. Routine investigations showed normal blood counts with raised Erythrocyte sedimentation rate (ESR) which was 58 mm/after 1 hr and raised C-reactive protein (CRP). Routine urine tests and blood biochemistry were within normal limits. HIV, VDRL tests were negative and Mantoux test showed positive reaction. Primary staining of discharge was negative for bacteria, fungi and mycobacteria. Skin biopsy from the lesion was subjected to culture on LJ media and histopathological examination. On culture there was yellowish, rough colony which grew after 21 days of inoculation which was confirmed as Mycobacterium tuberculosis by PCR [Figure 3]. Histopathology study of skin biopsy revealed epithelioid granuloma with inflammatory cell infiltrates in the dermis [Figure 4]. The chest X-ray of anterior-posterior (AP) and lateral view showed no infiltration. X-ray of the right humerus AP/lateral view showed features of periosteal reaction with new bone formation and soft tissue showed irregular radiolucent areas in the margin [Figure 5]. These findings were suggestive of chronic osteomyelitis. Basing on the above positive findings the case was diagnosed as scrofuloderma associated with chronic osteomyelitis of the right arm.

Figure 1

Multiple lesions with papulopustular lesions on right arm

Figure 3

Positive result on pcr for Mycobacterium tuberculosis

Figure 4

Epitheloid cell granuloma and inflammatory cells(H and E, ×100)

Figure 5

X-ray of right humerus showing features of chronic osteomyelitis

Closure view of the lesion

Patient was put on anti tubercular therapy showed improvement and complete cure occurred after one year.

Discussion

The prevalence of Tuberculosis is around 30 million globally and approximately one third of the cases are found in India.[8] Cutaneous tuberculosis remains a rare entitity and is an uncommon form of extrapulmonary tuberculosis infection. Even in India tuberculosis is an endemic disease but cutaneous outbreaks are rare that is less than 0.1%. It remains as a challenge for clinicians when it is presented as papules nodules or ulcers.[9] Scrofuloderma usually spreads by endogenous source that is from extension of an underlying lymphadenitis, synovitis or osteomyelitis.[10] In skeletal tuberculosis the clinical findings may not be specific and in many cases the radiolodical features resemble pyogenic osteomyelitis, so it is frequently neglected or misdiagnosed.[2] Spine and hip are the most common sites of osteoatrticular tuberculosis, but tuberculosis of humerus is less common. In our case, scrofuloderma was confirmed by the presence of acid fast bacilli on culture which was confirmed by PCR and presence of epithelioid granulomas on histopathologic examination. Basing on the radiological findings TB osteomyelitis of humerus was confirmed. The positive family history, histopathological study, positive Mantoux test, X ray results, followed by culture and PCR results confirmed the case as Scrofuloderma co-existing with chronic osteomyelitis of humerus due to Mycobacterium tuberculosis. The patient was treated successfully with anti-tubercular drugs.

Conclusion

Tuberculosis is an important public health problem in India. Scrofuloderma remains a diagnostic and therapeutic challenge as the clinical appearance is not always characteristic and a positive culture result is not always obtained. In endemic areas like India the unusual presentations of tuberculosis should be kept in mind to avoid delay in diagnosis and institution of appropriate antitubercular therapy.

What was known?

Humerus is anuncommon site for tuberculous osteomyelitis. Isolated osteomyelitis of Humerus presenting as scrofuloderma is less often seen.