Cutaneous tuberculosis with features suggestive of scrofuloderma masquerading as hidradenitis suppurativa: a case report

Abstract

Scrofuloderma is a form of cutaneous tuberculosis that results from the spread of infection from an underlying focus, most commonly lymph nodes or bone, to the overlying skin. It shares overlapping features with various other cutaneous diseases, such as hidradenitis suppurativa. We report a 47-year-old woman presenting with a 4-year history of anterior chest swelling and a 2-year history of a right axillary mass that had ruptured spontaneously. The patient had undergone multiple incisions and drainage procedures and received several courses of antibiotics with limited success. Diagnostic investigations including imaging, biopsy, and ultrasound-guided cartridge-based nucleic acid amplification test supported a diagnosis of cutaneous tuberculosis with features suggestive of scrofuloderma involving the right axilla. The patient was subsequently initiated on antitubercular therapy. Cutaneous tuberculosis should be considered in the differential diagnosis of chronic or recurrent atypical cutaneous lesions in regions with a high burden of tuberculosis.

Plain language summary

Chest wall and armpit swellings caused by tuberculosis mistaken for a common skin disease

A 47-year-old woman presented with painful, recurrent swellings on her chest and underarm, which were initially diagnosed as hidradenitis suppurativa, a chronic inflammatory skin condition. Despite multiple courses of antibiotics and repeated surgical drainage, her symptoms persisted and recurred, making management challenging. Further evaluation, including imaging and laboratory analysis of fluid and tissue samples from the affected areas, revealed cutaneous tuberculosis. The specific form, scrofuloderma, occurs when tuberculosis infection spreads from nearby lymph nodes into the overlying skin. Following the correct diagnosis, the patient was started on standard anti-tuberculosis therapy, leading to clinical improvement. This case highlights how tuberculosis can mimic other chronic skin diseases, particularly in regions where tuberculosis is common. It emphasizes the importance of reconsidering the diagnosis in patients who do not respond to conventional treatment. Early and accurate identification of the underlying cause can prevent unnecessary procedures, reduce inappropriate antibiotic use, and ensure timely initiation of effective therapy.

Introduction

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is a serious infectious disease and represents a significant global health burden.^1,2 Cutaneous tuberculosis (CTB) accounts for approximately 1.5%–3% of all extrapulmonary manifestations of TB. ³ Scrofuloderma is a form of cutaneous tuberculosis resulting from contiguous spread from an underlying focus. ³ Commonly affected areas include the neck (parotid, submandibular, and supraclavicular), axilla, and inguinal regions. ⁴ Hidradenitis suppurativa (HS) is a chronic inflammatory disease of intertriginous areas presenting with nodules, abscesses, and scarring. ⁵ Differentiating between these two conditions can be challenging, particularly when systemic symptoms are minimal or absent.

Case report

A 47-year-old woman of Indian origin presented to our tertiary care center in South India with a 4-year history of anterior chest swelling that had previously been treated with multiple sessions of incision and drainage, with recurrence in the past few months. She also reported a right axillary swelling that had ruptured spontaneously 2 years earlier, for which she received several courses of antibiotics with only limited improvement. The chronological progression of the patient’s symptoms and investigations is summarized in Figure 1. The patient had no known history of prior TB, no documented TB contacts, no diabetes mellitus, and no immunosuppressive drug use. The patient belonged to a lower socioeconomic background. On physical examination, a subcutaneous swelling measuring approximately 10 × 3 cm in the midsternal region, located about 5 cm below the suprasternal notch, was identified (Figure 2). The overlying skin was pinchable, and the lesion exhibited limited mobility in both vertical and horizontal planes. Additionally, puckered and linear scars were observed on the right axilla with sinus tract formation. Based on the patient’s history and symptoms, several differential diagnoses were considered, including scrofuloderma, hidradenitis suppurativa, and other bacterial and fungal infections.

Figure 1.

Timeline of patient symptoms and interventions.

Figure 2.

Subcutaneous abscess observable on the anterior chest along the midsternal line.

A complete workup was initiated, with routine laboratory investigations being unremarkable. To further evaluate the midsternal swelling and exclude thoracic involvement, a computed tomography (CT) scan of the chest was performed. The scan revealed a well-defined, multiloculated collection anterior to the sternum, measuring 9 × 3 cm, without significant bone changes or intrathoracic extension and normal lung parenchyma (Figure 3). The findings were suggestive of an infectious collection, with active tuberculosis being a prime consideration. To confirm the suspicion, fluid aspiration was performed under ultrasound guidance. The aspirate subsequently tested positive for Mycobacterium tuberculosis via CBNAAT, with no rifampicin resistance identified. Additional non-tuberculous mycobacterial, bacterial, and fungal cultures of the fluid tested negative. A skin biopsy of the axillary swelling was done, revealing granulomatous inflammation with focal areas of necrosis (Figures 4 and 5), a histopathological finding consistent with cutaneous tuberculosis (CTB). Sputum cultures for Mycobacterium tuberculosis tested negative. Serological testing for human immunodeficiency virus (HIV) was also negative.

Figure 3.

CT scan of the chest shows a well-defined multiloculated mass located anterior to the sternum, suggestive of an infectious collection.

Figure 4.

Swelling/lesion of the right axillary region.

Figure 5.

Histopathological slide of the right axillary lesion.

Based on the clinical, microbiological, and histopathological data, a diagnosis of cutaneous tuberculosis with features suggestive of scrofuloderma was made. After consultation with the infectious diseases team, the patient was initiated on standard first-line antitubercular therapy (isoniazid, rifampicin, pyrazinamide, and ethambutol) for 2 months (intensive phase), followed by isoniazid and rifampicin for 4 months (continuation phase). The patient maintained full adherence to therapy, monitored through monthly follow-ups and patient self-reporting. Over the course of her treatment, the anterior chest wall abscess ruptured spontaneously (Figure 6). The patient demonstrated significant clinical improvement after initiation of antitubercular therapy. The size of the swelling gradually reduced, induration decreased, and discharge diminished by the fourth to sixth week of treatment. Complete healing of the draining sinus and scarring was observed during follow-up, and no recurrence was noted during the subsequent months of clinical monitoring. This case report was conducted and reported in accordance with the CARE guidelines ⁶ (Supplemental Material).

Figure 6.

Post-treatment ruptured midsternal abscess on anterior chest.

Discussion

TB continues to be a significant global disease, specifically in developing countries. The World Health Organization (WHO) reports that India accounts for approximately 25% of the global tuberculosis burden as of 2025, making it the largest contributor to TB cases worldwide.^1,2 CTB represents a small proportion of extrapulmonary TB, with scrofuloderma being the most common form in developing countries such as India. ³ The clinical presentation of scrofuloderma may overlap with several dermatological and infectious conditions. Important differential diagnoses include hidradenitis suppurativa, bacterial abscesses, sporotrichosis, blastomycosis, actinomycosis, tubercular chest wall abscess, pyoderma gangrenosum, cutaneous sarcoidosis, and cutaneous malignancies. The patient in our case was a middle-aged female belonging to a lower socioeconomic background, which is a recognized epidemiological risk factor for tuberculosis. During physical examination, linear and puckered scars were visualized on her neck and right axillary regions, indicating previous interventions. The patient received multiple empirical antibiotic courses and underwent repeated incision and drainage procedures with only limited improvement, leading to an initial misdiagnosis as recurrent bacterial abscess or hidradenitis suppurativa. TB was not suspected due to the absence of systemic symptoms and the lesion’s resemblance to superficial abscesses, resulting in a delayed diagnosis.

Based on the patient's age, medical history, and physical examination findings, two differential diagnoses were mainly considered: Cutaneous TB (scrofuloderma) and Hidradenitis suppurativa. Hidradenitis suppurativa was considered due to the lesion’s apocrine location, scarring, chronicity and abscess formation, ⁷ whereas scrofuloderma was considered due to its recurrence, location of the lesions overlying lymph nodes, chronic swelling, scarring, and poor response to antibiotics.^3,4 Radiological CT showed a well-defined multiloculated lesion anterior to the sternum, indicative of an infective collection, suggesting active tuberculosis. Ultrasound-guided aspiration of the right axillary swelling fluid tested positive for Mycobacterium tuberculosis using cartridge-based nucleic acid amplification test (CBNAAT), which also showed rifampicin sensitivity; the test has a specificity and sensitivity of 90.3% and 79.3% for extrapulmonary samples, respectively. ⁸ CBNAAT detects Mycobacterium tuberculosis and identifies rpoB gene mutations associated with rifampicin resistance, allowing rapid differentiation between rifampicin-sensitive and rifampicin-resistant tuberculosis and enabling initiation of standard first-line therapy in sensitive cases. ⁸ Drug susceptibility testing was not performed as CBNAAT demonstrated rifampicin sensitivity. Additional cultures of the aspirated fluid for non-tuberculous mycobacteria, bacteria, and fungi were negative.

However, negative cultures despite positive CBNAAT may occur in paucibacillary extrapulmonary tuberculosis. ⁹ Although scrofuloderma classically arises from contiguous spread of infection from an underlying lymph node or bony focus, no such focus was demonstrable on CT imaging in this case. Therefore, the diagnosis of scrofuloderma remains presumptive. It is possible that an occult lymph node focus was present but not detected radiologically, as has been described in paucibacillary extrapulmonary tuberculosis. ¹⁰ Additionally, the positive CBNAAT result supports endogenous spread from a likely occult tuberculous lymph node focus. Histopathological examination demonstrating granulomatous inflammation with caseous necrosis further supported a tuberculous etiology, a pattern frequently observed in cutaneous tuberculosis, including scrofuloderma. The presence of chronic sinus formation, characteristic scarring, granulomatous inflammation with caseous necrosis on histopathology, and microbiological confirmation of Mycobacterium tuberculosis strongly supported the diagnosis of cutaneous TB.

Based on these diagnostic findings, the lesions were diagnosed as cutaneous TB with some features suggestive of scrofuloderma. Sputum culture of the patient was negative, indicating no pulmonary involvement. The patient was also tested for human immunodeficiency virus (HIV) due to the increased susceptibility of individuals with HIV infection and immunocompromised individuals to scrofuloderma, for which she tested negative. ⁴ Cutaneous tuberculosis is generally treated using the same regimen as pulmonary tuberculosis, with treatment duration typically ranging from 6 to 9 months, depending on clinical response. In the present case, initiation of standard antitubercular therapy resulted in clinical improvement with no recurrence during follow-up. Scrofuloderma shares overlapping features with various cutaneous manifestations. Chen et al. ¹¹ describe scrofuloderma as “the great imitator” due to its similarity to other skin lesions. Kim et al. ¹² report a case of scrofuloderma which was initially misdiagnosed as a bacterial abscess. The right diagnosis was made only when the antibiotic therapy was ineffective. Other cases where scrofuloderma presented with characteristics suggestive of HS have also been described.^10,13 Garon et al. ¹⁰ document a case where the diagnosis of scrofuloderma was made due to recurrence of the lesions despite antibiotic therapy. Muller et al. ¹³ also show a similar timeline of antibiotic therapy and recurrence, leading to the identification of scrofuloderma. As shown in Table 1, both conditions may present with chronic nodules, abscess formation, and scarring in intertriginous regions, which can lead to misdiagnosis in the absence of microbiological evaluation.

Table 1.

Key differences between scrofuloderma and hidradenitis suppurativa.

Features	Scrofuloderma	Hidradenitis suppurativa
Pathogenesis	Endogenous spread from an underlying tuberculous focus 3	Caused by follicle occlusion 5
Site of infection	Areas overlying infected lymph nodes, particularly the neck, axillae, chest wall, and groin 4	Intertriginous areas such as axillae, inframammary folds, groin, perineum or the buttocks 5
Morphological features	Reddish brown nodules or swellings that form discharging sinus tracts with watery, purulent or caseous material 4	Erosions or ulcerations, inflamed nodules, and abscesses, epithelized tunnels with purulent discharge 5
Pain	Usually no pain 4	Painful 5
Associated systemic symptoms	Usually absent or mild, particularly in isolated cutaneous disease.	None/insignificant.
Microbiological stains	Positive AFB stain or detection of Mycobacterium tuberculosis by molecular methods. 3	Usually negative for AFB; bacterial cultures may show secondary infection. 5

AFB, Acid Fast Bacilli.

Conclusion

This case highlights the importance of thorough diagnostic evaluation for diseases that share similar characteristics. Recurrent infections should prompt careful evaluation of alternative differential diagnoses or may lead to prolonged antibiotic therapy, causing not only further recurrence but also treatment fatigue. Recurrent HS is often treated with tumor necrosis factor alpha (TNF-α) inhibitors, which are known to exacerbate latent tuberculosis. Hence, diagnostic caution is essential in refractory cases of hidradenitis suppurativa, as such presentations may represent cutaneous tuberculosis with features suggestive of scrofuloderma. Early diagnosis and comprehensive patient-centered care are key factors in achieving the wider goal of ending the TB epidemic.

Supplemental Material

sj-docx-1-tai-10.1177_20499361261449091 – Supplemental material for Cutaneous tuberculosis with features suggestive of scrofuloderma masquerading as hidradenitis suppurativa: a case report

Supplemental material, sj-docx-1-tai-10.1177_20499361261449091 for Cutaneous tuberculosis with features suggestive of scrofuloderma masquerading as hidradenitis suppurativa: a case report by Midhun Raj, Tarun Kumar Suvvari, Vimal Thomas, Anand Krishnan R. G., Aishwarya Nitin Dnyate, Ryan Chris Thaddaeus, Noel Thomas Kandathil and Tejinder Singh in Therapeutic Advances in Infectious Disease