Citations

Although the majority of giant cell tumors (GCTs) of the bone occur in adult patients, occasionally they arise in the pediatric population. In this setting they may be mistaken for tumors more commonly seen in this age group, including osteosarcoma, aneurysmal bone cyst, and chondroblastoma. All cases of primary GCT of the bone arising in patients 18 years and below were retrieved from our institutional archives and examined with emphasis on the evaluation of various morphologic patterns. Clinical/radiologic records were reviewed when available. Analysis for H3F3A/H3F3B mutations was performed in a subset of cases. Sixty-three (of 710) patients treated at our institution for GCT were 18 years of age and below. The following morphologic patterns were identified: fibrosis (31 cases, 49%), reactive-appearing bone (26, 41%), cystic change (7, 11%), foamy histiocytes (6, 10%), secondary aneurysmal bone cyst (3, 5%), and cartilage (2, 3%). Infarct-like necrosis was present in 17 tumors (27%), and the mitotic rate ranged from 0 to 35 mitoses/10 high-power fields (median 5 mitoses/10 high-power field). Follow-up information (n=55; 6 mo to 69.6 y; median, 11.6 y) showed 21 patients with local recurrence (38%) and 2 patients with lung metastasis (4%). Polymerase chain reaction with sequencing showed that 5 of 5 tested cases harbored H3F3A mutations. In summary, GCT arising in the pediatric population is rare, representing 9% of GCTs seen at our institution. The morphologic spectrum of these tumors is broad and similar to that seen in patients above 18 years of age. It is important to recognize that matrix formation may be observed in GCT, including reactive-appearing bone and cartilage, as well as areas of fibrosis mimicking osteoid production, to avoid misclassification as osteosarcoma or other giant cell–rich lesions common in children.

Migraine preventive medications are used to reduce the frequency, severity, and disability of migraine attacks. Once migraine preventive therapy is initiated, the question of how long to maintain this therapy arises. This article will explore the literature pertaining to the long‐term use of migraine preventive medications, including length of treatment and safety with long‐term exposure.

AimsBiphenotypic sinonasal sarcoma (SNS) is a locally aggressive tumour that occurs in the sinonasal region. PAX3–MAML3 has recently been identified as a recurrent fusion gene event in this entity; however, a subset of tumours harbour alternative PAX3 rearrangement without the involvement of MAML3. In this study we sought to characterize the molecular profile of a large series of cases, with a special emphasis on tumours with alternative fusions.Methods and resultsForty‐four examples of SNS were screened by fluorescence in‐situ hybridization and reverse transcription polymerase chain reaction to better characterize its molecular profile and identify potential novel fusion genes. Twenty‐four were positive for PAX3–MAML3 (55%), 15 showed rearrangements of PAX3 without MAML3 involvement (34%), one showed rearrangement of MAML3 without PAX3 involvement, and four were negative for the involvement of either gene (9%). Among 15 cases with PAX3 involvement only, three were found to harbour PAX3–FOXO1. Two of these cases arose in the nasal cavities of female patients (aged 31 and 47 years), and one showed bilateral involvement of the nasal cavities of a 35‐year‐old male. A fourth case involved the skull base of a 47‐year‐old male, and was positive for PAX3–NCOA1. Patients with fusion‐negative tumours were slightly older.ConclusionMore than half of the SNSs in this series were positive for PAX3–MAML3. However, a subset of tumours may harbour alternative PAX3 fusion genes or show no involvement of PAX3. Except for a possible weak association between age and molecular profile, the overall morphological and immunophenotypic features of all cases seem to be similar. Because of the rarity of these tumours, the impact of the molecular profile on the clinical course of these tumours remains to be determined.