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 Table of Contents  
Year : 2017  |  Volume : 22  |  Issue : 2  |  Page : 107-109

Tuberculosis of foot mimicking mycetoma

1 Department of Pulmonary Medicine, King George's Medical University, Lucknow, Uttar Pradesh, India
2 Department of Medicine, MRA Medical College, Ambedkar Nagar, Uttar Pradesh, India

Date of Web Publication15-Sep-2017

Correspondence Address:
Surya Kant
Department of Pulmonary Medicine, King George's Medical University, Lucknow, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jmgims.jmgims_190_14

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Skin tuberculosis (TB) is a relatively uncommon form of extrapulmonary TB. Even in the countries with high pulmonary TB loads, cutaneous TB (CTB) cases are rarely reported. Here, we report a case of 35-year-old male who presented with diffuse swelling and multiple discharging sinuses over the right foot for 7 years nonresponding to any kind of treatment which was confused with mycetoma but the etiology came out to be tubercular on further workup leading to the diagnosis of CTB. This case highlights the importance of suspecting CTB particularly in a geographical area where TB in every form is very much predominant.

Keywords: Foot, mycetoma, sinus, skin tuberculosis

How to cite this article:
Prakash V, Verma AK, Joshi A, Kumar V, Kant S, Mishra AK. Tuberculosis of foot mimicking mycetoma. J Mahatma Gandhi Inst Med Sci 2017;22:107-9

How to cite this URL:
Prakash V, Verma AK, Joshi A, Kumar V, Kant S, Mishra AK. Tuberculosis of foot mimicking mycetoma. J Mahatma Gandhi Inst Med Sci [serial online] 2017 [cited 2023 Feb 7];22:107-9. Available from: https://www.jmgims.co.in/text.asp?2017/22/2/107/214743

  Introduction Top

Tuberculosis (TB) remains one of the leading infectious causes of death worldwide. TB is one of the most common, rampant infectious diseases in underdeveloped countries, and the number of cases in industrialized countries has increased in recent years. The incidence of extra-pulmonary TB (EPTB) is also increasing but due to high pulmonary TB load, this area is not gaining focus of the practitioners. Moreover, it is highly confused with leprosy or mycetoma if it involves the peripheries. In this part of the world (India), where both these entities are common cutaneous TB (CTB) is commonly misdiagnosed as mycetoma or leprosy. CTB occurs when there is an invasion of skin, a natural barrier by Mycobacterium tuberculosis(MTB). The causative agent of skin TB is an acid-fast Bacillus (AFB). MTB, Mycobacterium bovis and under certain conditions the Bacillus Calmettee-Guerin (BCG), an attenuated strain of M. bovis cause skin TB.

  Case Report Top

A 35 years nondiabetic nonhypertensive male, a farmer by occupation presented to our outpatient department with a complaint of swelling over the dorsum of the right foot since 7 years [Figure 1] and [Figure 2]. It was not tender and was associated with off and on fever since 1 year and loss of weight since 6 months. Loss of appetite was also present. Gradually, the swelling became hard and progressed with the formation of multiple discharging sinuses over the course of time in spite of treatment from a general practitioner. The patient consulted a dermatologist at this stage where a culture for fungal elements and biopsy was done. Culture came to be sterile, and biopsy showed the possibility of mycetoma [Figure 3]. He was prescribed tablet dapsone 100 mg 1 h.s, tablet cotrimoxazole 1 b.d and tablet terbact 250 mg 1 o.d. However, there was no response to the treatment. Swelling over the foot progressed gradually involving the whole of the dorsum, medial malleolus and the lower third of leg with multiple discharging sinuses. Skin became puckered and excoriated due to itching. On pressing the swelling, there was a discharge of purulent and foul-smelling pus. A right nontender inguinal lymphadenopathy also appeared. There was no history of BCG vaccination or any trauma.
Figure 1: Dorsum of foot showing swelling and discharging sinuses

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Figure 2: Lateral view of dorsum of foot showing swelling and discharging sinuses

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Figure 3: Biopsy showing mycetoma

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Routine investigations were nonsignificant except for mild anemia. Viral markers for HIV, hepatitis C virus, and hepatitis B virus were nonreactive. X-ray foot anteriorposterior and the lateral view were done which showed no involvement of bones. X-ray chest was also within normal limits. Pus was sent for MTB culture from our side that showed growth of MTB complex. Polymerase chain reaction (PCR) test of the pus showed the presence of MTB complex DNA. As there was no previous history of antitubercular treatment in past patient was started on rifampicin, isoniazid, ethambutol, and pyrazinamide as per weight. He improved gradually as there was a progressive decrease in the size of swelling [Figure 4] and [Figure 5]. He is in our regular follow-up and improving day by day.
Figure 4: Dorsum of foot showing healed sinuses and improvement in swelling

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Figure 5: Lateral view of dorsum of foot revealing healed sinuses and decrease in swelling

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  Discussion Top

TB remains one of the leading infectious causes of death worldwide.[1] TB is one of the most common, rampant infectious diseases in underdeveloped countries, and the number of cases in industrialized countries has increased in recent years as a result of the increased incidence of HIV, AIDS, and drug resistance.[2] CTB describes dermatological manifestations of TB involving the skin, which can be caused by MTB, M. bovis, and the BCG vaccination.[3] These lesions can be acquired exogenously or endogenously, although the former route is significantly less common. Although CTB is reported as <1% of all cases of TB,[3] it is important for practitioners to consider this infection when faced with a suggestive clinical picture.

Despite the fact that it can affect any organ or site of the body, the breasts, skeletal muscles, and spleen are considered the most resistant organs to TB.[4] Isolated cutaneous involvement of TB is rare. Underlying systemic involvement of TB is often seen in CTB, especially in children. Early classification of CTB was based only on lesion morphology. Tappeiner and Wolff proposed the most widely accepted classification based on the route of infection.[4] An additional classification designed to enhance the Tappeiner and Wolff system allows further distinction using bacterial load. In this classification, CTB is classified into multibacillary and paucibacillary forms. In the multibacillary forms, mycobacteria can easily be identified on histological examination utilizing the Ziehl-Neelsen staining (AFB) method and culture.[5] In the paucibacillary sparse Bacilli are seen on histological examination and culture isolation is rare.[6]

Direct exogenous inoculation of MTB into the skin of a susceptible person may lead to TB verrucosa cutis, TB chancre, and in some cases Lymphogranuloma venerum like an infection. Endogenous infection occurs in previously infected person via lymphatic, hematogenous spread, or contiguous extension. Hematogenous spread is seen in acute miliary TB, metastatic TB abscess (gummatous TB), papulonecrotic tuberculid (PNT), and Lymphogranuloma Venerum like infection. Contiguous extension results in scrofuloderma and orificial tuberculoid. CTB can again be classified as true TB or tuberculids.[7] True CTB comprises tuberculous chancre, miliary TB, lupus vulgaris, scrofuloderma, TB verrucosa cutis, tuberculous metastatic abscess, and orificial TB. Tuberculids are delayed sensitivity reactions to MTB in patients having a strong immune response. Lichen scrofulosorum and PNT are examples of tuberculids. Facultative tuberculids consist of erythema induratum and erythema nodosum. Erythema induratum can be defined as a subcutaneous nodule that is recurrent and painful presenting usually on the posterior aspect of the leg; biopsy of which shows lobular panniculitis with vasculitis and granulomatous inflammation. Eythema nodosum is a painful subcutaneous nodule, occurring mostly over the anterior aspect of the legs and hands. Biopsy shows septal panniculitis with an absence of vasculitis and usually without granuloma. Erythema nodosum occurs in association with a granulomatous disease such as sarcoidosis, TB, and granulomatous colitis. TB remains an important cause of erythema nodosum in endemic countries.

Clinical manifestations of CTB are variable. Constitutional symptoms such as fever, weight loss, night sweats, or a failing of general health are infrequently encountered. Patients usually have a positive tuberculin skin test.

Differential diagnosis most often includes carcinoma. Less common differentials are blastomycosis and actinomycosis.

An accurate diagnosis is usually made on histopathology by demonstrating a classical caseation, AFB within such a lesion and/or by demonstrating epitheloid granulomas, Langhans giant cells, and lymphocyte aggregates. Though the diagnosis is mainly based on the identification of tubercle Bacilli, it has been recognized that an AFB-positive smear is not always sufficient evidence for a definitive diagnosis of MTB.[8] Differentiation of MTB from mycobacteria other than tuberculosis species is essential. Cultures and AFB staining are negative in most cases. Often failure to demonstrate necrosis on fine needle aspiration cytology does not exclude TB because of the small quantity of the sample examined. Still biopsy is the most reliable test. PCRs are highly sensitive especially in culture-negative specimens from paucibacillary forms of the disease.[9] Another great advantage of this system is that it does no show cross-reactivity with actinomycetoma species such as Actinomadura or Nocardia.[10] Reliable identification of causal agents to the genera Actinomadura, Nocardia, and Streptomyces can be achieved by PCR and sequencing.[10] However, the identification to the rank of species still cannot be achieved even with PCR.[10]

Antituberculous chemotherapy is the main treatment for CTB. No specific guidelines are available for its treatment. The disease should be treated as any other form of EPTB. Antituberculous therapy comprise rifampicin, isoniazid, pyrazinamide, and ethambutol for the initial 2 months, which is then followed by rifampicin and isoniazid for another 4 months.

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Conflicts of interest

There are no conflicts of interest.

  References Top

WHO Global Tuberculosis Report; 2013. Available from: http://www.who.int/tb/publications/global_report/gtbr13. [Last Accessed on 2014 Dec 25].  Back to cited text no. 1
Handog EB, Gabriel TG, Pineda RT. Management of cutaneous tuberculosis. Dermatol Ther 2008;21:154-61.  Back to cited text no. 2
Frankel A, Penrose C, Emer J. Cutaneous tuberculosis: A practical case report and review for the dermatologist. J Clin Aesthet Dermatol 2009;2:19-27.  Back to cited text no. 3
Lai-Cheong JE, Perez A, Tang V, Martinez A, Hill V, Menagé Hdu P. Cutaneous manifestations of tuberculosis. Clin Exp Dermatol 2007;32:461-6.  Back to cited text no. 4
Tan SH, Tan BH, Goh CL, Tan KC, Tan MF, Ng WC, et al. Detection of Mycobacterium tuberculosis DNA using polymerase chain reaction in cutaneous tuberculosis and tuberculids. Int J Dermatol 1999;38:122-7.  Back to cited text no. 5
Bravo FG, Gotuzzo E. Cutaneous tuberculosis. Clin Dermatol 2007;25:173-80.  Back to cited text no. 6
Barbagallo J, Tager P, Ingleton R, Hirsch RJ, Weinberg JM. Cutaneous tuberculosis: Diagnosis and treatment. Am J Clin Dermatol 2002;3:319-28.  Back to cited text no. 7
Kao PT, Tu MY, Tang SH, Ma HK. Tuberculosis of the breast with erythema nodosum: A case report. J Med Case Rep 2010;4:124.  Back to cited text no. 8
Katoch VM. Newer diagnostic techniques for tuberculosis. Indian J Med Res 2004;120:418-28.  Back to cited text no. 9
van de Sande WW, Fahal AH, Goodfellow M, Mahgoub el S, Welsh O, Zijlstra EE. Merits and pitfalls of currently used diagnostic tools in mycetoma. PLoS Negl Trop Dis 2014;8:e2918.  Back to cited text no. 10


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]


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