Case #248 - March, 2009

A 36-year-old immigrant from Mozambique presented to his health care provider with heartburn and chronic right abdominal pain. All previous ova and parasite (O&P) examinations were negative. An endoscopy was performed, upon which a worm-like object was observed in the ascending colon near the ileocecum. The suspicious object, measuring approximately 7 mm in length, was removed, collected in 10% formalin, and sent to Pathology for work-up. The object was sectioned, stained with hematoxylin and eosin (H&E) and reviewed by the attending pathologist, who in turn captured the following images and sent them to DPDx for telediagnosis assistance. What is your diagnosis? Based on what criteria?

Figure A

Figure B

Figure C

Figure D

Figure E

Case Answer

This was a case of trichuriasis, caused by Trichuris trichiura. Diagnostic features included:

the location in the host (colon).
a marked difference in the size of the anterior and posterior ends of the body (Figure A), with a long, slender anterior end (shown in cross-sections to the left) and a shorter, thicker posterior end (shown as a transverse section to the right).
a thick cuticle with annulations (arrow, Figure B and CU, Figure D).
a thin hypodermis (HY, Figure D) containing nuclei.
the presence of polymyarian muscle cells (PO, Figure D) beneath the hypodermis.
a thick-muscled cloaca (arrow, Figure C).
the presence of bacillary bands (BB, Figure E), a stichocyte (ST, Figure E), and stichosome nucleus (SN, Figure E) in the anterior section of the specimen.