Ear and Temporal Bone Pathology: Neural, Sclerosing and Myofibroblastic Lesions

Abstract

Neural, sclerosing, and myofibroblastic lesions of the ear and temporal bone present diagnostic challenges for both clinicians and pathologists due to significant overlap in their clinical presentations, histologic appearances, and immunohistochemical profiles. While some of these lesions, such as schwannomas, are relatively common, others are rendered even more difficult because they are encountered very rarely in routine surgical pathology practice. This review is intended to provide an update on the pathology of some of the most commonly encountered primary diagnostic entities for the ear and temporal bone, and includes the following neural lesions: schwannoma, meningioma, and encephalocele/meningocele. Sclerosing lesions that will be discussed include spindle cell and sclerosing rhabdomyosarcoma, sclerosing epithelioid fibrosarcoma, and sclerosing paraganglioma. Finally, myofibroblastic lesions that will be reviewed are nodular fasciitis, IgG4-related disease, and solitary fibrous tumor. For each of these lesions, the differential diagnosis and useful ancillary tests will be discussed in the context of a broad range of additional primary and secondary lesions.

Preoperative Embolization of a Solitary Fibrous Tumor Originating from External Auditory Meatus: A Case Report with Literature Review

“…CD34 is a characteristically overexpressed antigen in SFTs [ 16 ], though it can be lost in some malignant SFTs [ 17 ]. Significant number of cases show also a CD99 and B-cell lymphoma protein 2 (Bcl-2) positivity, but are usually negative for S-100, desmin, nuclear β-catenins, cytokeratins and other muscular, vascular, neural and epithelial markers [ 8 , 9 , 13 , 17 , 18 ]. Immunohistochemical analysis distinguishes these tumors from other microscopically similar spindle-cell and mesenchymal neoplasms that also can be found in the external auditory meatus, such as schwannoma or fibroma [ 6 , 16 ].…”

“…Immunohistochemical analysis distinguishes these tumors from other microscopically similar spindle-cell and mesenchymal neoplasms that also can be found in the external auditory meatus, such as schwannoma or fibroma [ 6 , 16 ]. Benign fibrous histiocytoma, sarcomatoid carcinoma as well as well-vascularized pathologies like vascular malformation, vascular metastasis, angiosarcoma, high-grade sarcoma or venous varix also have to be excluded [ 18 , 19 ]. The Ki-67 marker can be used to assess the proliferation rate [ 20 ].…”

Tumor Fibroso Solitário do Canal Auditivo Externo: Uma Entidade Rara

“…[5][6][7] Muitas vezes este tipo de tumor é erroneamente diagnosticado como outros tumores mais comuns da cabeça e pescoço, como o angiofibroma, no entanto apresenta características histológicas e imuno-histoquímicas diferenciadoras. 7 As características microscópicas levam à suspeição do diagnóstico de TFS, em particular pela observação de células fusiformes ou ovais, dispostas num padrão aleatório, com alternância de áreas constituídas essencialmente por colagénio e áreas hipercelulares, 10 mas não são suficientes por si só para diferenciar o TFS de outros tumores benignos de tecidos moles, como perineuromas, lipomas de células fusiformes, fibromatose desmoide e sarcomas de células fusiformes. 10,11 Antigamente o TFS era classificado como hemangiopericitoma, mas pelo facto do primeiro ter uma origem fibroblástica e não pericítica, estas são hoje classificadas como diferentes entidades.…”

“…7 As características microscópicas levam à suspeição do diagnóstico de TFS, em particular pela observação de células fusiformes ou ovais, dispostas num padrão aleatório, com alternância de áreas constituídas essencialmente por colagénio e áreas hipercelulares, 10 mas não são suficientes por si só para diferenciar o TFS de outros tumores benignos de tecidos moles, como perineuromas, lipomas de células fusiformes, fibromatose desmoide e sarcomas de células fusiformes. 10,11 Antigamente o TFS era classificado como hemangiopericitoma, mas pelo facto do primeiro ter uma origem fibroblástica e não pericítica, estas são hoje classificadas como diferentes entidades. A presença de áreas hipocelulares preenchidas de forma densa por colagénio e a imunorreatividade ao CD34 distinguem o TFS do hemangiopericitoma.…”

Case Report: Radiological Features of Sclerosing Epithelioid Fibrosarcoma in the Right Fibula

“…It has been reported to have relatively high incidence of local recurrence (>50% of cases), metastasis (40-80% of cases) and tumor-related mortality (2,3). SEF typically involves the extremities or the torso (2), followed by the abdominal viscera (4,5) and head and neck areas (6)(7)(8). Primary SEF in the bone was first reported in 2001 (9).…”