Shigenori Yonemura md, Department of Urology, Mie University School of Medicine, 2-174, Edobashi, Tsu-city, Mie 514-8507, Japan. Email: email@example.com
Abstract Tuberculids of the penis are extremely rare. The clinical features of tuberculids of the penis have been reported as ulceration or scars. We have experienced a case of tuberculid of the penis that appeared as a scab on nodule. A 56-year-old man presented with a 4-month history of a painless subcutaneous nodule at the glans penis. Pathological findings of the nodule showed granulomatous inflammation. Tuberculin tests were strongly positive, but tubercle bacilli could not be detected. The diagnosis was tuberculid of the penis and the patient received antituberculosis chemotherapy. The present paper reports an interesting and rare case of tuberculid of the penis with a scab on nodule.
Tuberculosis (TB) of the penis has been seen in many countries; however, tuberculids of the penis are extremely rare, particularly outside Japan. Clinical features of tuberculids of the penis have been reported as ulceration or scars.
We report a case of a tuberculid of the penis that appeared as a nodule without ulceration, but had a scabbed nodule.
A 56-year-old man presented with a 4-month history of a painless subcutaneous nodule at the glans penis. The surface was covered with almost normal skin, but there was a small scab on the nodule (Fig. 1). He had no history of tuberclosis, genitourinary infections or trauma. Prostate, epididymis and testicular examinations were normal. Diagnostic excision of the nodule was performed. Microscopic examination of the pathological specimen showed granulomatous inflammation with a Langhans’ giant cell and necrosis intermingled with erythrocytes, neutrophils and macrophages (Fig. 2).
Tuberculosis was highly suspected. Tuberculin tests were strongly positive (20 × 21 mm induration and 30 × 35 mm erythema). No acid-fast test bacilli were observed on Ziehl- Neelsen staining. A polymerase chain reaction (PCR) study of this specimen using probes for M. tuberculosis, M. avium and M. intracellulare detected none of the specific DNA. Full blood count and blood chemistry tests were within normal limits. Active lesions of pulmonary tuberculosis or another tuberculous lesion were not found on chest X-ray or computed tomography scans. Urinalysis showed no abnormalities and intravenous pyelography revealed no evidence of tuberculosis in the urinary tract. In spite of repeated cultures of sputum, gastric fluid and stool, M. tuberculosis could not be detected.
Treatment with antituberculosis chemotherapy (300 mg Isoniazid, 450 mg Rifampicin and 750 mg Ethanbutol) was initiated. Marked improvement was seen in the nodule of the glans after 6 months of treatment.
Tuberculid of the penis is extremely rare and has mainly been reported from Japan.1–4 Tuberculid of the penis is included in the cutaneous tuberculosis. First, we need to understand the difference between cutaneous tuberculosis and tuberculids. Rook et al. divided cutaneous tuberculosis into two types.5 One is progressive tuberculosis, in which tubercle bacilli are present, and the other is eruptive tuberculosis, in which tubercle bacilli are not present. Tuberculids belong to the latter type. The concept of tuberculids was introduced by Jean Darier in 1896.6 Tuberculids have been considered as skin eruptions due to an allergic or hypersensitivity reaction to the tubercle bacilli or one of its constituent parts. Generally, tuberculids are diagnosed by the following findings: a positive tuberculin test, tubeculous involvement of lymph nodes or internal viscera or both, absence of tubercle bacilli from skin biopsy or culture and resolution of the eruption with antituberculosis therapy.7 Recently, for the detection of tubercle bacilli, PCR for specific DNA has been introduced.8 Tuberculosis has been diagnosed clearly and rapidly using by PCR. In the present case, pathological findings showed granulomatous inflammation with a Langhans giant cell and there was a positive tuberculin test. Although thesample of skin biopsy showed an absence of tubercle bacilli and negative PCR results, his eruption improved with antituberculosis threapy. Therefore, we , we diagnosed the case as a tuberculid.
Tuberculids are classified into three types in Western countries, depending on clinical features and histological depth: lichen scrofulosorum, papulonecrotic tuberculid and erythema induratum.7 Lichen scrofulosorum has superficial dermal guranuloma which are composed of epitheloid cells with some Langhans’ giant cells and a narrow margin of lymphoid cell. Papulonecrotic tuberculid, which involves the upper dermis extending to the epidermis, shows the eruption of necrotizing papules. Erythema induratum, which histologically involves subcutaneous tissue, reveals persistent and recurring nodular lesions, usually in the legs of women.7 In Japan, another type of tuberculid, named penis tuberculid, has been considered a disease entity. In 1950, Yanagihara reported many cases of penis ulcers of tuberculous origin in detail.9 He showed the anatomical and clinical features of penis tuberculid as follows: a nodule arises in the deep part of the glans or around the urethra, some are absorbed spontaneously, while others gradually come up to the surface and begin to ulcer. The ulcer or nodules are mainly limited in the glans. Strictly speaking, there are slight differences between penis tuberculid (tuberculid of the penis) and papulonecrotic tuberculid; however, several penis tuberculids have been reported as papulonecrotic tuberculids. Most cases showed ulceration or scars;2–4 however, penis tuberculid without ulceration has only reported by Kashima et al. Histopathologically, in the present case, the nodule existed in the subcutaneous lesion of penis and had a scab on the nodule. We believe that the nodule with a cab is an early stage of the tuberculid. Therefore, in the present case, ulceration might occur following progression, but the relation between the nodule and ulceration of penis has not been clarified.
Tuberculids of the penis are extremely rare and many urologists are not familiar with this disease. However, there has recently been a worldwide explosion in its incidence and, consequently, a resurgence of skin tuberculosis and tuberculids.10 This phenomenon has been attributed to the HIV epidemic, the emergence of resistant strains of M. tuberculosis, the ease of migration and a decline in TB control efforts. Although penis tuberculid is unusual, especially when it appears as a nodular lesion, we should be reminded of this important disease in the case of an undiagnosed nodule in the penis.