Lupus vulgaris: residual granulomatous reaction after antituberculous treatment

ARTICLE

Auteur(s) : Shinji NODA¹, Yuichiro TSUNEMI^1,2, Mayuko ARAKI¹, Shinichi SATO¹ m31071@gmail.com

¹ Department of Dermatology, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan

² Department of Dermatology, Tokyo Women's Medical University, Tokyo, Japan

A 66-year-old Japanese female presented with a 3-month history of a gradually enlarging erythematous plaque on the left cheek, without generalized symptoms. An atrophic indurated erythematous plaque measuring 6 cm in diameter was present, with a small ulcer (figure 1A). The patient had no underlying complications causing immunodeficiency, such as HIV infection, diabetes mellitus, or malignancy. Mycobacterium tuberculosis was isolated from a culture of necrotic tissue from the ulcer. The isolated strain was sensitive to all four antituberculous drugs, isoniazid, rifampicin, pyrazinamide, and ethambutol. Purified protein derivative testing showed an induration of 17 mm. Chest X-ray and chest computed tomography demonstrated multiple nodules on bilateral lungs, indicating pulmonary tuberculosis. M. tuberculosis was also identified in the sputum by culture and polymerase chain reaction. Histological examination of the skin biopsy specimen demonstrated a caseating granulomatous reaction with dense infiltrate of lymphocytes (figures 1B, C).

Lupus vulgaris (LV) was diagnosed, associated with pulmonary tuberculosis. Multiple drug therapy, consisting of isoniazid (300 mg), rifampicin (450 mg), pyrazinamide (1,200 mg), and ethambutol (750 mg), was given for 2 months, followed by treatment with isoniazid and rifampicin for 4 months. After treatment, the induration was reduced and the ulcer disappeared (figure 1D). Biopsy of the skin lesion revealed the disappearance of caseation, and a reduction in the size and number of epithelioid tubercles and lymphocytic infiltrate (figures 1E, F). On chest computed tomography, the size of multiple nodular lesions was reduced, but they were not cleared. The patient did not show up for the follow-up visit. Eight months after completion of the treatment, she revisited our department with a further reduction of the skin induration and no changes in the lung nodules (figure 1G).

LV is a paucibacillary form of cutaneous tuberculosis, which usually results from hematogenous or lymphatic dissemination of Mycobacterium tuberculosis from an endogenous primary site of infection [1, 2]. Notably, in the present case, identification of the skin lesion led to the diagnosis of an active lung tuberculosis requiring treatment. The high frequency of false-negative results of cultures, smears, and polymerase chain reaction analyses from skin specimens leads to misdiagnosis and delayed treatment [3]. Importantly, Kilic et al. [3] reported that 3 of 11 patients with cutaneous tuberculosis had lung lesions. Treatment delay results in exacerbation of pulmonary tuberculosis, which is more life-threatening. Thus, physicians should be aware of this differential diagnosis when finding ulcerative or indurated plaque-like lesions.

In our case, although cutaneous tuberculosis showed significant clinical and histopathological improvement, the indurated plaque on the face and granulomas in the skin biopsy specimen were not completely removed after antituberculous therapy. Ramesh et al. [4] reported that localized LV in 37/38 patients was clinically and histopathologically cured 16 weeks after starting multiple drug treatment. LV in the remaining patient was cured in 18 weeks. In comparison, our patient showed a significantly delayed response to treatment. One possible explanation is the size of the lesion. While the lesions were less than 2.5 cm in the previous report, in our patient it measured 6 cm in diameter. Moreover, imaging studies of the lung after treatment showed residual nodular lesions. While multidrug-resistant tuberculosis strains do exist in Japan [5], the M. tuberculosis strain in our case showed no resistance to antituberculous drugs. Importantly, the skin lesion continued to improve clinically, with no progression in the lung lesions, during the 8 months after completion of the treatment, suggesting granulomatous reactions sometimes remain for months after treatment, despite the disappearance of M. tuberculosis. Our case demonstrated that observation for relapse rather than additional antituberculous treatment may be appropriate, even if complete resolution of LV is not achieved shortly after treatment.

Disclosure

Financial support: none. Conflict of interest: none.

References

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