Answer: Oncocercoma due to Onchocerca volvulus
An oncocercoma is a tumor-like subcutaneous nodule containing male and female worms. The female with the characteristic "double barrel uterus structure" of filarial worms releases larvae into the surrounding tissue The larvae then migrate through the skin and into the eye, causing debilitating dermatitis and ocular damage, eventually leading to blindness.
I always point out to my students that infection with this filarial worm is different than infection with Wuchereria bancrofti, Brugia, and Loa loa, in which the ADULT worm that causes the majority of symptoms. Instead, the symptoms are due to the migrating larvae.