[8] LGFMS generally presents as a painless mass located in the subcutaneous or subfacial (i.e. beneath the skin) tissues of the upper or lower limbs, trunk,[4] or, less commonly, the head and neck areas or within the gastrointestinal tract, heart, kidney, brain,[11] retroperitoneum, mediastinum, or abdominal cavity.

Magnetic resonance imaging and computed tomography scans often give results suggesting that a tumor is a LGFMS.

[4][14] LGMFS tumors typically contain one or multiple nodules embedded in a grey-white whorled cut surface.

Microscopic histopathologic views of hematoxylin and eosin stained tumor tissue show whorled and bundled, uniform, bland-appearing, slender fibroblastic spindle-shaped cells with elongated, tapered nuclei.

The spindle-shaped cells typically occur in an alternating fibrous and myxoid (i.e. more blue or purple compared to normal connective tissue because of excessive uptake of the hematoxylin stain) background.

This hybrid pattern is more often seen in recurrent and metastatic LGGMS tumors, may progress to dominate the tissues, and may therefore warrant changing the diagnosis of LGFMD to sclerosing epithelioid fibrosarcoma.

[10][13] The diagnosis of LGFMS rest primary on its tumors' histology consisting of spindle-shaped fibroblastic cells in the appropriate background that express the MUC4 protein and either a FUS-CREB3L2, FUS-CREB3L1, EWSR1-CREB3L2, or EWSR2-CREBL1 fusion gene in most cases.

[8] Magnetic resonance imaging and computed tomography scan findings ma also help in the diagnosis.

[19] The generally recommended treatment for LGFMS is aggressive, wide surgical excision of the tumor[8] including even those located in difficult to access sites such as the mediastinum.

[7][10][6] However, the experiences with radiation therapy and chemotherapy to treat LGFMS are limited and this tumor does not appear very sensitive to either treatment modality.