The American journal of surgical pathology
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Am. J. Surg. Pathol. · Oct 2009
Hybrid schwannoma/perineurioma: clinicopathologic analysis of 42 distinctive benign nerve sheath tumors.
Benign nerve sheath tumors include neurofibromas, schwannomas, and perineuriomas. In recent years, nerve sheath tumors showing discrete areas of more than one histologic type have been described. We have recently recognized tumors showing hybrid features of schwannoma and soft tissue perineurioma. ⋯ Degenerative nuclear atypia (akin to that seen in ancient schwannoma and atypical neurofibroma) is relatively common. Hybrid schwannoma/perineuriomas have no evident association with neurofibromatosis and rarely recur. The pathogenetic basis of the dual pattern of differentiation in these lesions remains poorly understood at this time.
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Am. J. Surg. Pathol. · Sep 2009
RT-PCR analysis for FGF23 using paraffin sections in the diagnosis of phosphaturic mesenchymal tumors with and without known tumor induced osteomalacia.
Phosphaturic mesenchymal tumors of the mixed connective tissue type (PMTMCT) are extremely rare, histologically distinctive neoplasms, which cause tumor-induced osteomalacia (TIO) in most cases through the elaboration of a phosphaturic hormone, fibroblast growth factor-23 (FGF23). Rarely, identical tumors without known TIO may be observed. We studied a large group of PMTMCT for expression of FGF23, using a novel reverse transcription polymerase chain reaction (RT-PCR) assay for FGF23 in formalin-fixed, paraffin-embedded tissues. ⋯ FGF23 gene expression was present in more than 90% of PMTMCT with known TIO, confirming the role of FGF23 in this syndrome. Rare FGF23-negative PMTMCT with known TIO likely express other phosphaturic hormones (eg, frizzled-related protein 4). Our finding of expression of FGF23 in 75% of histologically identical tumors without known TIO confirms the reproducibility of the diagnosis of PMTMCT, even in the absence of known phosphaturia.
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Am. J. Surg. Pathol. · Aug 2009
Case ReportsIgG4-related sclerosing pachymeningitis: a previously unrecognized form of central nervous system involvement in IgG4-related sclerosing disease.
IgG4-related sclerosing disease is a distinctive mass-forming lesion with frequent systemic involvement, most frequently the pancreas, salivary glands, and lacrimal glands. This report describes a case manifesting with a previously unrecognized form of central nervous system involvement. The 37-year-old man presented with signs and symptoms of spinal cord compression at the thoracic level 9. ⋯ The patient also had a 1-year history of bilateral submandibular swelling due to chronic sialadenitis. Thus, IgG4-related sclerosing pachymeningitis represents a new member of the IgG4-related sclerosing disease family affecting the central nervous system. It seems that at least a proportion of cases described in the literature as idiopathic hypertrophic pachymeningitis belong to this disease, especially as some patients have other clinical manifestations compatible with IgG4-related sclerosing disease, such as cholangitis and orbital pseudotumor.
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Am. J. Surg. Pathol. · Jul 2009
Focal myositis: a clinicopathologic study of 115 cases of an intramuscular mass-like reactive process.
Focal myositis is an uncommon inflammatory pseudotumor of skeletal muscle that can be confused with a variety of neoplastic and inflammatory diseases. It is often misunderstood because it presents as a tumor-like mass, but histologically resembles a skeletal muscle myopathy or dystrophy. We wanted to discuss the detailed morphologic and immunophenotypic features of the largest reported group of focal myositis patients. ⋯ Focal myositis occurs in specific muscle groups of young adults of both sexes without significant trauma. It is a largely unrecognized entity with specific histology including myopathic, focal neurogenic, fibrosis, and inflammatory features. It can be easily mistaken for an inflammatory myopathy, dystrophy, alternate reactive, or even neoplastic process. Focal myositis seems to be a macrophage and T-cell-rich lesion that changes to B cell and dendritic plasmacytoid cells when markedly inflamed, but does not seem to have a known viral or molecular etiology. IgG4 presence may be linked to the fibrosis in these lesions; a possible transient autoimmune etiology cannot be excluded. Careful attention to reproducible clinicopathologic features can aid diagnosis and spare patients from excessive surgery or adverse therapy.
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Am. J. Surg. Pathol. · Jun 2009
Mucoepidermoid carcinoma of the cervix: another tumor with the t(11;19)-associated CRTC1-MAML2 gene fusion.
Mucoepidermoid carcinoma (MEC) of the uterine cervix is a controversial entity. By strict morphologic criteria, the tumor has features identical to those of salivary gland MEC and is characterized by nests composed of 3 cell types (epidermoid, intermediate, and mucin producing) in the absence of overt glandular differentiation. Nonetheless, the entity is not recognized in the current World Health Organization classification of cervical tumors. ⋯ All MEC showed aberrations of at least 1 of the loci, whereas none of the cervical adenosquamous carcinomas harbored rearrangements or amplification of either locus. Our results demonstrate that cervical tumors defined as MEC by strict morphologic criteria harbor genetic aberrations involving the genes characteristically rearranged in MEC of the salivary glands, and suggest that cervical MEC is an entity distinct from conventional cervical adenosquamous carcinoma. The development of drug therapy targeted to the genes rearranged in MEC underscores the importance of correct classification of cervical MEC because the diagnosis may hold therapeutic implications different from other cervical malignancies.