ABSTRACT
Solitary fibrous tumors (SFTs) are rare mesenchymal tumors that can occur at any location. Since the identification of specific NAB2-STAT6 fusion in SFTs, the fusion gene variants, NAB2 exon 4-STAT6 exon 2/3 and NAB2 exon 5/6/7-STAT6 exon 16/17/18, have been reported to be associated with clinicopathological features, and the latter variant is predominant in meningeal SFTs. SFTs developing in the salivary glands are rare, and more rarely, those involving ectopic salivary glands (ESGs) have been reported in the cerebellopontine angle (CPA); however, their characteristics remain not well understood. In this study, we performed a clinicopathological and molecular analysis of 3 cases of meningeal SFT with ESGs. All cases presented with an extra-axial mass in the CPA, which is a rarer location for intracranial ESGs compared to the sellar region. Histologically, except for the presence of ESGs, there was no significant difference between current cases and ordinary SFTs. The ESGs demonstrated no cellular atypia, and although the spindle tumor cells were immunopositive for STAT6, the ESGs were negative in all cases, supporting that the ESGs are non-neoplastic components. In 1 case, ESGs were found only in the primary tumor and disappeared in recurrence/dissemination. Of note, molecular analysis identified NAB2 exon 4-STAT6 exon 2 in all cases. In conclusion, our results suggest that ESGs particularly in the CPA may be associated with SFTs and that meningeal SFTs with ESGs may be associated with the minor fusion variant of NAB2-STAT6 in the intracranial lesions.
Subject(s)
Meningeal Neoplasms , Soft Tissue Neoplasms , Solitary Fibrous Tumors , Humans , Cerebellopontine Angle/metabolism , Cerebellopontine Angle/pathology , Oncogene Proteins, Fusion/genetics , Repressor Proteins/genetics , Repressor Proteins/metabolism , Solitary Fibrous Tumors/genetics , Solitary Fibrous Tumors/pathology , STAT6 Transcription Factor/genetics , Meningeal Neoplasms/genetics , Salivary Glands/metabolism , Biomarkers, Tumor/genetics , Gene FusionABSTRACT
We report a case of primary low-grade lymphoma of mucosa-associated lymphoid tissue (MALT) arising from the kidney in a 30-year-old man with an abdominal mass in the right flank detected by ultrasonography. Radical nephrectomy was performed under a preliminary diagnosis of renal cell carcinoma. The final histological diagnosis was MALT-type lymphoma. To the best of our knowledge, only five reports of primary MALT-type lymphoma in the kidney have been published in the literature so far. All cases were surgically treated and only one case went on to chemotherapy postoperatively.