Miliary tuberculosis (MTB) is a severe form of tuberculosis in which the instigating bacteria— Mycobacterium tuberculosis or potentially a relative that infects cows and deer, Mycobacterium bovis—spread widely through the body and create small lesions. The name “miliary” dates back to 1700, when a physician noted that the specks resembled millet seeds.

While Mycobacterium can spread through the air and are often found in the lungs, the bacteria can strike anywhere in the body. Still, penile tuberculosis is exceedingly rare. In fact, it’s uncommon to have tuberculosis erupt anywhere in the urinary and genital tracts. Among the infections that spring up in the region, penile infections account for less than 1 percent.

But, given the man’s lungs and his immunosuppressed status, the unusual presentation became their leading guess—and tests soon confirmed it. Mycobacterium were identified in the man’s respiratory tract, and penile tissue tested also showed the bacteria, though the testing couldn’t identify what species of Mycobacterium.

Treatment for tuberculosis requires a regimen of several antibiotics and takes months. In the man’s case, they customized his treatment with a 12-month, four-drug regimen that wouldn’t interfere with his transplant.

Still, the penile lesion got worse before it got better. He developed a large necrotic ulceration on the side of his penis, and his foreskin began to “break down.” Surgeons had to mechanically cut out the dead tissue. After 10 months, his infection appeared to have cleared, and his penile lesion had improved.

Unexplained exposure

It remains unclear how the man got the infection. He told doctors he wasn’t aware of coming in contact with any tuberculosis patients and wasn’t in settings where the bacteria normally spread, such as prisons. It’s possible that the bacteria had been lurking in his transplanted kidney.