Member-only story
Inflammatory Myofibroblastic Tumor
Lessons From the Friday Unknowns
Histologic sections show a lesion with extensive coagulative necrosis. There is no evidence lymph node in this specimen.
![](https://miro.medium.com/v2/resize:fit:684/1*9jT1Uu7B_Yy-lfe7LSyUbA.png)
The lesion is composed of numerous spindle cells associated with inflammatory cells including lymphocytes, eosinophils and neutrophils, the latter near the areas of necrosis.
![](https://miro.medium.com/v2/resize:fit:700/1*7RSZHar_h24EsFWDnLsrZA.png)
![](https://miro.medium.com/v2/resize:fit:700/1*9M18lbg9TtXR721_njQuQQ.png)
The spindle cells are arranged in loose fascicles or are more spread out and are arranged in a stellate fashion resembling, in part, granulation tissue. Mitotic figures are identified.
![](https://miro.medium.com/v2/resize:fit:700/1*xnXsO0qSG_tcBo__G_nW4g.png)
The spindle cells are positive for smooth muscle actin, CD10 and BCL-6 (moderate), and are negative for CD1a, CD3, CD5, CD20, CD21, CD30, CD31, CD34, CD68, PAX-5, BCL-2, cyclin D1, keratin (AE1/AE3), desmin, S100 protein, HHV8 and STAT6. The antibody specific for Ki-67 highlights…