An unusual episode of lupus vulgaris masquerading as sporotrichosis

Case 1 A 24‐year‐old man presented with asymptomatic, gradually progressive plaques and nodules over the right knee extending to the thigh in a linear pattern of 3 months' duration. A year previously, he had been diagnosed with tuberculosis of the spine and had been advised to take antitubercular treatment; however, he chose to stop treatment on his own after 4 months of therapy as his spinal condition improved with a marked decrease in pain. There was no history of fever, systemic complaints, or any spinal or knee injury preceding the disease. His mother had received treatment for pulmonary tuberculosis 4 years previously. Dermatologic examination revealed well‐defined, brownish papules, plaques, and nodules of variable sizes, ranging from 3 cm to 6 cm, present over the right knee and front of the thigh in a linear pattern. The lesions were soft in consistency with ‘‘apple‐jelly’' nodules and the surrounding skin showed atrophic scarring ( Fig. 1 ). Plaques and nodules in a sporotrichoid distribution over the right lower limb (Case 1) image All the hematologic and biochemical investigations were normal except for an elevated erythrocyte sedimentation rate (ESR) (48 mm/1 h). Venereal disease research laboratory (VDRL) test, enzyme‐linked immunoabsorbent assay (ELISA) for human immunodeficiency virus (HIV), and sputum examination for acid‐fast bacilli (AFB) were negative. Mantoux test with 1 tuberculin unit (TU) of purified protein derivative‐standard (PPD‐S) showed an induration of 25 × 20 mm. Blood culture and culture of the tissue homogenate for Mycobacterium tuberculosis , atypical mycobacteria, and fungal organisms revealed no growth. Slit skin smears from the plaque showed only lymphocytes and a few neutrophils. Immunoenzymatic test (ELISA) for antimycobacterial immunoglobulin M (IgM) antibody against the A 60 antigen complex was strongly positive (> 1 : 200 U). Histopathologic examination revealed a hypertrophic epidermis with noncaseating tuberculoid granulomas consisting of lymphohistiocytes, epithelioid cells, and Langhans' giant cells in the papillary and upper reticular dermis ( Fig. 2a,b ). No AFB were detected. Polymerase chain reaction (PCR) and guinea pig inoculation could not be performed due to a lack of facilities. (a) Photomicrograph showing noncaseous tuberculoid granulomas in the papillary dermis (hematoxylin and eosin, × 40); (b) photomicrograph showing Langhans' giant cells (arrow) in the dense granuloma image Skiagram of the chest was normal, although X‐ray of the lumbosacral spine revealed bony destruction of the sacral foramina. A magnetic resonance image (MRI) in the sagittal and axial plane was suggestive of caries of the fifth lumbar and sacral vertebrae with a large presacral and anterior epidural collection ( Fig. 3 ). Computed tomography (CT) scan‐guided abscess drainage of the sacral region was performed and microscopic examination of the fluid revealed lymphocytes, polymorphs, macrophages, and a few AFB in a necrotic background. Magnetic resonance image in the sagittal plane: caries of the fifth lumbar and sacral vertebrae suggestive of Pott's spine image A diagnosis of lupus vulgaris (LV) of the right lower limb with Pott's spine was made and the patient was administered antitubercular therapy consisting of rifampicin (450 mg), isoniazid (INH) (300 mg), ethambutol (800 mg), and pyrazinamide (1500 mg) daily for 2 months, followed by two drugs (rifampicin and INH) for 4 months. With this, his cutaneous lesions resolved completely with cribriform scarring in 6 months. Treatment was continued for Pott's spine for another 6 months as advised by the orthopedist. Case 2 A 30‐year‐old man presented with ulcerated plaques and nodules in a linear arrangement over the left foot extending to the lower leg of 5 months' duration. A history of blunt trauma preceding the appearance of the lesions was present. He had no systemic complaints and his family history was not contributory. Cutaneous examination revealed a soft, reddish‐brown ulcerated plaque, 8 × 3 cm in size with ‘‘apple‐jelly’' nodules, on the dorsum of the left foot and linear nodular lesions over the leg ( Fig. 4 ). There was no lymphadenopathy and his systemic examination was within normal limits. A bacillus Calmette–Guérin (BCG) scar was present over the left arm. Ulcerated plaques and nodules in a linear distribution over the left leg (Case 2) image His ESR was elevated (36 mm/1 h). Mantoux test with 1 TU PPD‐S showed an induration of 30 mm. HIV was nonreactive. Mycobacterial and fungal cultures from the tissue homogenate revealed no growth. Histopathologic examination from the plaque revealed noncaseating tuberculoid granulomas in the papillary dermis suggestive of LV. Similar to the first case, he was also advised to take antitubercular therapy consisting of four drugs (INH, rifampicin, pyrazinamide, ethambutol) for 2 months, followed by two drugs (INH, rifampicin) for the next 4 months. The lesions resolved completely with puckered scarring.