Signs heralding appearance of thymomas after extended thymectomy for myasthenia gravis

Thymomas appear very rarely after extended thymectomy for early-onset myasthenia gravis (EOMG). We describe 2 such cases that highlight potential early warning signs.

In their 20s, one woman and one man developed EOMG (AChR antibody-positive), requiring extended transsternal removal of hyperplastic thymi at ages 35 and 27, respectively. Their myasthenia gravis was readily controlled for the next 10 and 7 years before deteriorating in both, with appearance of late clinical features and anticytokine autoantibodies suggesting underlying thymomas, namely respiratory infections, genital herpes, chronic candidiasis, and alopecia in the woman and erythroderma and lichen planus in the man, followed by Pseudomonas, Klebsiella, and cytomegalovirus infections plus chronic hepatitis during intensifying immunosuppressive therapy. Type B thymomas were then detected. Despite surgery or radiotherapy, and intensive drug therapy, the patients died 7 and 1 years later.

Certain infections/dermatologic manifestations that associate with long-standing thymomas may herald their late appearance, despite previous thymectomy.