This pattern resembles
nodular fasciitis or may have a granulation tissue-like appearance.
[19]
Nodular fasciitis mimicks Pleomorphic adenoma with presence of spindle and plasmacytoid cells.
Nodular fasciitis is a benign proliferative lesion of soft tissue with unknown etiology.
In addition to the above-mentioned tumors with fibroblast or myofibroblast features, there are still other tumors with different surgical treatment and prognosis needed to be distinguished with desmoplastic fibroblastoma such as
nodular fasciitis, sclerotic fibroma, neurofibroma, and low-grade fibromyxoid sarcoma.
(1) This entity belongs to a greater family of benign pseudosarcomatous lesions including proliferative fasciitis,
nodular fasciitis, and intravascular fasciitis.
(1,7) It has often been underreported and clinically mistaken for a hernia, suture granuloma, desmoid tumor,
nodular fasciitis, lipoma, sarcoma, or metastatic malignancy.
(2,4) However, they are distinct from desmoid tumors, fibromatoses, and
nodular fasciitis. (4) There is also evidence that tumefactive fibroinflammatory lesions may be predisposed by radiation therapy, (1) as evidenced by the presence of pseudoepitheliomatous hyperplasia, chronic inflammation, extensive fibrin deposition, and fibrinoid necrosis of blood vessels in this case.
Various differentials of reactive and neoplastic processes, which give similar appearances including
nodular fasciitis, proliferative fasciitis inflammatory myofibroblastic tumors (IMTs), fibromatoses, pseudolymphomas, Kaposi sarcomas, fibrosarcomas, and lymphomas were kept.
The differential diagnosis of intramuscular myxomas includes also aggressive angiomyxoma, myxoid neurofibroma, myxoid liposarcoma, cellular or juxta-articular myxoma, and
nodular fasciitis [18, 19].
Consequently, many different names have been assigned to this condition, including inflammatory pseudotumor,
nodular fasciitis, and pseudomalignant spindle cell proliferation [2, 3].
Cranial Fasciitis is very similar in microscopic findings to
nodular fasciitis, but it is characterized by a younger age of onset and different anatomic location.1 This entity has a predilection for the skull, with the temporoparietal region being most commonly affected.
The clinical differential diagnosis includes ranula, dermoid cyst, thyroglossal duct cyst, ectopic thyroid tissue, pleomorphic adenoma and mucoepidermoid carcinoma, angiolipoma, fibrolipoma and malignant lymphoma.9-11 A histopathologic differential diagnosis appropriate to the oral cavity would include fibrosarcoma if spindle cells are not localized and numerous.12 Other lesions should be also considered: they include schwanoma, myxoidneurofibroma, leiomyoma,
nodular fasciitis, myxolipoma, fibrolipoma, malignant fibrous histiocytoma, myxoidliposarcoma, and myxoid solitary fibrous tumor.