Case of the Week 35

Name 2 important histologic findings in the following bladder biopsies. (CLICK ON IMAGES TO ENLARGE)

Answer to Case 35

Answer: Urinary schistosomiasis with Schistosoma haematobium and adenocarcinoma of the bladder.

I admit that it wasn't quite fair to expect a diagnosis of cancer on just a few fields, but having seen this whole case, I can confirm that this is indeed adenocarcinoma. This is an unusual case, since schistosomiasis is usually associated with squamous cell carcinoma and not adenocarcinoma. However, it could be that the two findings are completely unrelated.

Of interest, you can see the terminal spine on one of the partially calcified eggs in the middle image, confirming that this is S. haematobium.

Case of the Week 34

Here is a simple identification. Feel free to be as general or as specific as you like, based on your expertise (and interest!).

Answer to Case 34

Wow, what a great response I had to this case! It is a beautifully ornamented tick, so I guess I'm not too surprised that it caught people's interest.

This is a male Amblyomma variegatum, also known as the Tropical African Bont Tick. It is found in the tropics and subtropics, including some islands of the Caribbean. You might notice from the photo that it has long mouth parts. Because of this, it tends to leave large (and painful) bite wounds.

It is a vector of several organisms causing veterinary disease (such as Heartwater fever), as well as Rickettsia africae, the agent of African tick-bite fever, and Crimean-Congo hemorrhagic fever virus. It may also carry a number of other viruses such as Dugbe, Thogoto, Bhanja , and Jos.

Congratulations to Karma453 for the correct answer, and to Anonymous for the follow-up answer. Also, special bonus points to F. and W. for their creative guesses that made me smile.

Case of the Week 33

The following lymph node biopsy was taken from a boy with no travel history outside of the U.S. He had presented with acute onset of fever and lymphadenitis.
Diagnosis? What is your differential diagnosis? (CLICK ON IMAGES TO ENLARGE)
Images courtesy of Dr. Thomas Trainer

Answer to Case 33

Answer: Toxoplasma gondii lymphadenitis. This is a rare case in that cysts are not typically seen in the affected lymph nodes. Instead, pathologists rely on the classic pathologic features (e.g. lymph node architecture and pattern of inflammatory cells) to suggest the diagnosis, which should then be correlated with clinical features and serologic tests.

Findings that may mimic the cysts of T. gondii include T. cruzi pseudocysts and macrophages with Leishmania spp. amastigotes or Histoplasma capsulatum yeasts.

Case of the Week 32

The following was extracted from the arm of a traveler to South America. Identification?

Answer to Case 32

Identity: fly larva of a myiasis-causing fly
Stedmans Medical dictionary defines myiasis as "Any infection due to invasion of tissues or cavities of the body by larvae of dipterous insects."

Ian was correct in identifying this larva as Dermatobia hominis. The adult fly of this species doesn't deposit its eggs on the skin itself, but instead places the eggs on other flying insects such as mosquitoes. The host fly then unwittingly deposits the eggs into a bite wound while taking a blood meal. Ingenious mechanism, huh? A simple mosquito bite can transmit so many organisms: Plasmodium parasites, yellow fever virus, dengue virus, encephalitis viruses, microfilariae, and tissue infesting maggots.