Cutaneous Tuberculosis: A Diagnosis Too Common, Yet Too Far

Akanksha Mahajan; Taru Garg; Kiran Agarwal; Varinder Singh

doi:10.4103/ipcares.ipcares_167_22

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CASE REPORT

Year : 2022 | Volume : 2 | Issue : 4 | Page : 230-232

Cutaneous Tuberculosis: A Diagnosis Too Common, Yet Too Far

Akanksha Mahajan¹, Taru Garg², Kiran Agarwal³, Varinder Singh¹
¹ Department of Pediatrics, Lady Hardinge Medical College and Kalawati Saran Children's Hospital, New Delhi, India
² Department of Dermatology, Lady Hardinge Medical College, New Delhi, India
³ Department of Pathology, Lady Hardinge Medical College, New Delhi, India

Date of Submission	08-Jul-2022
Date of Decision	27-Oct-2022
Date of Acceptance	29-Oct-2022
Date of Web Publication	29-Nov-2022

Correspondence Address:
Dr. Akanksha Mahajan
Department of Pediatrics, Lady Hardinge Medical College and Kalawati Saran Children's Hospital, New Delhi
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ipcares.ipcares_167_22

Abstract

Background: Cutaneous tuberculosis (TB) is a rare disease seen by the pediatrician on an outpatient basis. It has a varied presentation and is classified on the basis of the source of infection and host's immune response to mycobacteria. Lupus vulgaris (LV) is a paucibacillary manifestation of cutaneous TB. It can mimic other infectious skin diseases such as TB verrucosa cutis and chromoblastomycosis. Clinical Description: We hereby present a case report of an adolescent female with a serpiginous, nodular, and warty hyperpigmented skin lesion over her buttock. The lesion had started following incidental injury 7 years back as a papule and continued to expand despite multiple medications. Management: A skin biopsy was done which was suggestive of cutaneous TB, but the absence of systemic features confounded the diagnostic type. She was finally diagnosed as having LV after a detailed review with a dermatologist and pathologist. The patient responded well to antitubercular treatment. Conclusion: Although cutaneous tuberculosis is well described, it is often not recognized by the primary care physician. Diagnostic dilemmas may arise due to clinical-histopathological mismatch.

Keywords: Histopathology, lupus vulgaris, tuberculosis verrucosa cutis

How to cite this article:
Mahajan A, Garg T, Agarwal K, Singh V. Cutaneous Tuberculosis: A Diagnosis Too Common, Yet Too Far. Indian Pediatr Case Rep 2022;2:230-2

How to cite this URL:
Mahajan A, Garg T, Agarwal K, Singh V. Cutaneous Tuberculosis: A Diagnosis Too Common, Yet Too Far. Indian Pediatr Case Rep [serial online] 2022 [cited 2023 Jan 30];2:230-2. Available from: http://www.ipcares.org/text.asp?2022/2/4/230/362238

Tuberculosis (TB) in children remains a major health problem worldwide, especially in developing countries. Cutaneous tuberculosis (TB) is rare. It accounts for 1.5% of all cases of extrapulmonary TB.^[1] It has varied clinical presentations ranging from papules, nodules, ulcers, and papillomatous lesions depending on the route of entry of the bacilli and immune status of the host. The two most common forms of childhood cutaneous TB are lupus vulgaris (LV) and scrofuloderma. LV is a paucibacillary manifestation of cutaneous TB. It is characterized by nodular, sharply defined, gelatinous lesions with centralized atrophy. Although the clinical presentation is quite suggestive of the diagnosis, it often gets delayed due to poor recognition by the treating physician or pediatrician. In India, the reported prevalence of childhood skin TB varies from 18% to 54%.^[2] We report a case that was a diagnostic dilemma due to confounding clinical and histopathological interpretation.

Clinical Description

A 16-year-old girl came to the outpatient department with a skin lesion over her right buttock. It had appeared 7 years back following an incidental trauma with minimal bleeding. Thereafter, the lesion became dry, underwent scarring, and gradually expanded circumferentially. At presentation, there was no pus discharge, pain or itching locally. The surrounding skin was normal. The patient reported to have been seen by different physicians, advised multiple topical medications; the nature of which was not known, but the lesion continued to expand. There was no history of fever, cough, weight loss, anorexia, or contact with an active TB case. There was no history of any other skin lesion or similar lesion in any family member.

The patient weighed 55 kg and her height was 150 cm. Her body mass index was 24.4 Kg/m² normal for her age. Her heart rate was 88/min, respiratory rate 14/min, blood pressure 110/76 mm Hg and temperature 98.6F. There was no pallor or lymphadenopathy. On local examination, a nodular, warty, and hyperpigmented skin lesion was visible over the right buttock with serpiginous margins, measuring 8 cm × 14 cm. The temperature was not raised and there was no surrounding erythema. On systemic examination, respiratory examination revealed normal vesicular breath sounds, and no organomegaly was appreciated per abdomen. Other systems were normal.

Management and Outcome

The history of trauma implicated the possibility of exogenous contamination. However, the absence of fever and prolonged duration without complications did not favour a chronic infection. An autoimmune or allergic etiology seemed unlikely in the absence of history of disease flare-ups. On review of literature and images in an atlas, we suspected LV, TB verrucosa cutis (TVC), and chromoblastomycosis. Their clinicopathological comparison is presented in [Table 1].

Table 1: Differential diagnosis and pathological comparison

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A detailed evaluation was planned. Mantoux tuberculin skin test was positive (induration 32X28mm). Her abdominal sonogram and chest radiograph did not show any evidence of TB. A skin biopsy was performed. [Figure 1] shows the presence of many intraepidermal lymphocytes, and the dermis showed lymphocytes, plasma cells, and occasional histiocytes. Well-formed granulomas were seen in the lower dermis. Ziehl–Nielsen stain for acid-fast bacilli (AFB) was negative. Mycobacterium was not detected on cartridge-based nucleic acid amplification. Periodic acid–Schiff stain was also negative. This stain helps to demonstrate glycogen, cellulose, mucin, starch, and certain fungi such as Cryptococcus neoformans, Histoplasma capsulatum, Aspergillus fumigatus, and Blastomyces because of the high carbohydrate content in their cell wall/capsule. No fungal element was seen on the KOH mount and no fungal growth was observed after 5 weeks of incubation on Sabouraud agar, thereby ruling out chromoblastomycosis.^[3]

Figure 1: (a) Epidermis with granulation tissue in upper dermis, (b) Granuloma in lower dermis

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Although the histopathology report was suggestive of cutaneous TB, a diagnostic dilemma arose. Granulomas in the lower dermis pointed toward TVC, and this was also supported by the trauma. However, the dermatologists opinion based on clinical appearance was LV, though systemic manifestations of TB were absent. Since literature, reports clinicohistological concordance in 64%–85.6% cases of childhood cutaneous TB,^[4] it was decided to start antituberculous treatment (ATT). There was a significant response with reduction in size within a month and complete resolution by 4 months [Figure 2].

Figure 2: Warty lesion on the buttock, at 1 month following ATT, at 4 months of ATT. ATT: Antituberculous treatment

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Discussion

The clinicopathological manifestations of cutaneous TB are diverse. The precise diagnosis is often overlooked, due to confusing clinical presentations and no definitive diagnostic tool. The differential diagnosis includes sarcoidosis, leprosy, atypical mycobacterial infection, blastomycosis, chromoblastomycosis, actinomycosis, leishmaniasis, hypertrophic lichen planus, psoriasis, lupus erythematous, lymphocytoma, and Bowen's disease. The available investigative tools include Mantoux skin testing, chest X-ray, skin biopsy with histological analysis and special staining methods for identification of AFB, and cartridge-based nucleic acid amplification test; however, they have low sensitivity and specificity.

Cutaneous TB can be classified on the basis of the route of infection and pathogenic load. Multibacillary forms are detected in cutaneous tissue such as tuberculous chancre, scrofuloderma, orificial TB, acute miliary TB, and tuberculous gumma. Paucibacillary forms include TVC and LV. Direct inoculation of bacilli into the skin leads to chancre or TVC.^[5] Endogenous infection is secondary to a preexisting primary focus spreading contiguously (orificial TB and scrofuloderma), hematogeneously (acute miliary TB and tuberculous gumma), or through lymphatic dissemination (LV).^[1] On histopathology, intense caseation is seen in scrofuloderma, dermal granulomas, and pseudoepitheliomatous hyperplasia in TVC and upper dermal/epidermal granulomas without caseation in LV.^[6] According to a study conducted in an adult population from North India, the distribution of types of cutaneous TB was LV (55%), scrofuloderma (25%), orificial TB (5%), and TVC (5%).^[7] The most common sites involved were hands, feet, or buttocks.^[5]

Cutaneous TB may be an isolated finding as seen in our case or it may occur as disseminated TB in children. Case reports have described combinations of skeletal, ocular, and skin involvement making the diagnosis difficult.^[8] TB of the central nervous system, knee joint, and skin has also been reported in which diagnosis was mistaken for connective tissue disease.^[9] A common misdiagnosis is pyogenic abscess. The failure of therapeutic response to broad-spectrum antibiotics and isolation of mycobacteria establishes final diagnosis.^[10]

TVC starts as a single papule or nodule that slowly grows serpiginously as a warty hyperkeratotic plaque occurring at the site of trauma in individuals with strong immunity.^[4] It occurs without any systemic manifestations or lymphadenopathy. In comparison, LV is a chronic, progressive form that develops due to direct extension from underlying joints or lymph nodes through lymphatic or hematogeneous spread. LV presents with regional lymphadenopathy.

In conclusion, the diagnosis of LV can be considered in chronic painless skin lesions occurring as a direct extension of a TB focus, with strong Mantoux positivity, suggestive histopathological picture, and prompt response to ATT, especially in communities with high burden of cases of TB.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given consent for images and other clinical information to be reported in the journal. The guardian understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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