ABSTRACT
The boundaries of the benign spindle cell stromal tumors of the breast are still confusing. This is the reason why different names are interchangeably used for the same tumor and vice versa the same name for different tumors. Therefore, we studied the immunoexpression of easily available markers, such as CD34, α-smooth muscle actin, and desmin, with the addition of STAT6, as well as the chromosome 13q14 region by fluorescence in situ hybridization analysis in a series of 19 cases of benign spindle cell stromal tumors of the breast. Based on the morphologic and immunohistochemical findings, the following histotypes were identified: (i) tumors (10/19 cases) with the characteristic morphology of myofibroblastoma and stained with vimentin, CD34, desmin, and α-smooth muscle actin; (ii) fibroblastic benign spindle cell tumors (5/19 cases) composed of fibroblast-like cells stained only with vimentin and CD34; (iii) tumors (2/19 cases) with the typical morphologic features of solitary fibrous tumor and stained with vimentin, CD34, and STAT6; (iv) 1 case of spindle cell lipoma stained with vimentin and CD34; and (v) 1 case of fibroma composed of a paucicellular, diffusely hyalinized stroma with expression of vimentin and CD34. Notably most of the tumors, with the exception of solitary fibrous tumor, showed monoallelic deletion of FOXO1. This finding supports that myofibroblastoma, fibroblastic benign spindle cell tumor, spindle cell lipoma, and fibroma of the breast are histogenetically related lesions which belong to the same tumor entity.
Subject(s)
Biomarkers, Tumor , Breast Neoplasms/chemistry , Breast Neoplasms/genetics , Chromosome Deletion , Chromosomes, Human, Pair 13 , Neoplasms, Connective and Soft Tissue/chemistry , Neoplasms, Connective and Soft Tissue/genetics , STAT6 Transcription Factor/analysis , Stromal Cells/chemistry , Aged , Aged, 80 and over , Biomarkers, Tumor/analysis , Biomarkers, Tumor/genetics , Breast Neoplasms/classification , Breast Neoplasms/pathology , Breast Neoplasms, Male/chemistry , Breast Neoplasms, Male/genetics , Breast Neoplasms, Male/pathology , Female , Fibroma/chemistry , Fibroma/genetics , Fibroma/pathology , Genetic Predisposition to Disease , Humans , Immunohistochemistry , In Situ Hybridization, Fluorescence , Lipoma/chemistry , Lipoma/genetics , Lipoma/pathology , Male , Middle Aged , Neoplasms, Connective and Soft Tissue/classification , Neoplasms, Connective and Soft Tissue/pathology , Neoplasms, Muscle Tissue/chemistry , Neoplasms, Muscle Tissue/genetics , Neoplasms, Muscle Tissue/pathology , Phenotype , Predictive Value of Tests , Solitary Fibrous Tumors/chemistry , Solitary Fibrous Tumors/genetics , Solitary Fibrous Tumors/pathology , Stromal Cells/pathologyABSTRACT
Primary soft tissue tumors arising in the sinonasal tract are rare. While many mesenchymal neoplasms have been reported in the nasal cavity, sinuses, and nasopharynx, few are distinctive to this anatomic region. Some tumor types are relatively more common in this area, such as schwannoma and rhabdomyosarcoma. Nasopharyngeal angiofibroma and sinonasal hemangiopericytoma are unique entities of the sinonasal tract, as well as the recently characterized biphenotypic sinonasal sarcoma. This review discusses the clinical, morphologic, and immunohistochemical features and currently known molecular data of the more frequently encountered soft tissue tumors of the sinonasal tract.
