Morulae... in a Spleen and Liver?!

Here I am, just cruising around this spleen/liver combo sample from a 9 yo Lab with fever, lethargy, joint effusion/pain, and thrombocytopenia. It wasn’t indicated to me why the spleen and liver were aspirated (no masses described), but as I’m looking around....I start to notice these little cuties! Once I saw one, I noticed them pretty frequently.

Morulae! I’ve only personally seen morulae in neuts in blood smears and once in a joint effusion. So this was super fun to see in a spleen/liver sample!

Differentials for these are either Anaplasma phagocytophilum or Ehrlichia ewingii since those two organisms look the same on cytology. I suggested they do tick PCR (their SNAP was negative, but it can be negative in acute infections) to differentiate.

Cool, huh?!