RT @KarenFritchieMD: Cleveland Clinic soft tissue pathology course starts in 7 days!! May 15-18. 150 digital cases. 15 sessions with staff.….

RT @Nooshin_Dashti: Biphasic SS doesn't get better than this. IHC: AE1/AE3

Nice review article by Szczepanski, Westerhoff and Schechter on this rare entity (.

The spindled morphology and plexiform architecture can sometimes cause these tumors to be mistaken for (SDH-deficient) GIST. Unlike GIST, these tumors are negative for CD117 and DOG1.

It’s gastric and spindled, but it’s not a GIST… Plexiform fibromyxoma is a benign tumor that presents as a multinodular intramural mass in the stomach. The nodules can be fibrous or myxoid and have a delicate capillary pattern. #BSTPath, #UmichPath, #BSTpathGoBlue

RT @ScottBikeethan: Over the past several years, we have seen several examples and now you can read about our experiences with these patien….

Special thanks to colleague at U of Michigan for allowing me to share this case!.

Some nice papers (Fritchie and colleagues/ Chung and colleagues) further elaborating on this entity(ies)….

Fibromyxoid soft tissue tumors/fibroblastic lipoblastomas with a PLAG1 gene fusion often contain foci of myxoid stroma in the background of a more fibrous appearance. In addition to PLAG1 staining, these tumors usually show expression of desmin and CD34.

Dealing with an unusual fibromyxoid spindle cell neoplasm (that is MUC4 negative)? Consider PLAG1! #BSTPath, #UmichPath, #BSTpathGoBlue

I would highly recommend this course for anyone (regardless of level of expertise) looking for a comprehensive/case-based experience with bone and soft tissue. Dr. Fritchie and colleagues at Cleveland Clinic are excellent teachers.

Nice article on ALK-positive histiocytosis of the breast:

Interestingly, the cells in this case also showed staining for OCT2, which has historically been associated with other histiocytic-type proliferations, such as Rosai-Dorfman disease, some Langerhans cell histiocytosis, and juvenile xanthogranulomas.

The liberal use of ALK and histiocytic markers, with follow-up and molecular testing, can help ensure proper identification. These tumors, including the case presented here, often exhibit a KIF5B::ALK gene fusion.

Unlike IMT, the tumor cells of interest are negative for SMA and positive for PU.1. The cells exhibit more wrinkled and irregular nuclei, which can help suggest histiocytic differentiation.

ALK-positive histiocytosis of the breast is a rare tumor that can mimic other inflammatory neoplasms or processes, such as inflammatory myofibroblastic tumor, cellular spindled histiocytic pseudotumor (among others). #BSTPath, #UmichPath, #BSTpathGoBlue

Nice article by Sciallis, Chen and Folpe describing this entity.

Cellular spindled histiocytic pseudotumor (often of the breast) can sometimes be confused for inflammatory myofibroblastic tumor. The spindled cells exhibit irregular grooved nuclei which help suggest the tumor’s histiocytic nature. #BSTPath, #UmichPath, #BSTpathGoBlue

Nice article by Dermawan and colleagues on CD34-negative solitary fibrous tumors:.

Although not typically associated with a “round cell sarcoma” differential, solitary fibrous tumor can sometimes mimic small round cell type sarcomas such as Ewing sarcoma. #BSTPath, #UmichPath, #BSTpathGoBlue