Nodular Spindle Cell Vascular Transformation in Pelvic Lymph Nodes With Discovered on GIST1 (DOG1) Positivity Mimicking Metastatic Gastrointestinal Stromal Tumor

We present a case report of vascular transformation of lymph node sinuses (VTS) of nodular spindle cell variant. This variation is a rare, benign entity previously described with histopathologic transformation of lymph node sinuses into spindle cell nodules with or without vascular channels and associated sinusoidal fibrosis. This case highlights the diagnostic pitfall of discovered on GIST1 (DOG1) immunohistochemical staining of this entity, contributing to the initial misdiagnosis as metastatic gastrointestinal stromal tumor (GIST). To our knowledge, this is the first reported case of a patient with VTS and DOG1 positivity.