Case #384 – November 2014

A 73-year-old woman presented to a local clinic in Ghana with a skin nodule that had developed adjacent to the resection site of a previous low-grade malignant skin tumor. Biopsy specimens were collected and sent to a lab in the U.S. for histologic processing, including sectioning and staining with hematoxylin-and-eosin (H&E). Images of suspect structures were captured and sent to the DPDx Team for diagnostic assistance. Figures A–E show several of the images that were received for analysis. Neither sizes nor magnifications were provided with the images. What is your diagnosis? Based on what criteria?

Figure A

Figure B

Figure C

Figure D

Figure E

This was a case of onchocerciasis caused by Onchocerca volvulus. Diagnostic morphologic features included:

the presence of adult worms coiled within a subcutaneous nodule (Figure A).
weak, underdeveloped musculature (MU, Figure E).
paired uterine tubes with eggs (Figure D) and microfilariae (Figures C and E) in various stages of development. Notice also the small, simple intestine to the left of the uterine tubes in Figures D and E.

Figure E