RESUMO
Soft tissue angiofibroma is rare and has characteristic histomorphological and genetic features. For diagnostic purposes, there are no specific antibodies available. Fourteen lesions (6 females, 8 males; age range 7-67 years) of the lower extremities (12) and trunk (2) were investigated by immunohistochemistry, including for the first time NCOA2. NCOA2 was also tested in a control group of other spindle cell lesions. The known fusion-genes (AHRR-NCOA2 and GTF2I-NCOA2) were examined using RT-PCR in order to evaluate their diagnostic value. Cases in which no fusion gene was detected were additionally analysed by RNA sequencing. All cases tested showed nuclear expression of NCOA2. However, this was not specific since other spindle cell neoplasms also expressed this marker in a high percentage of cases. Other variably positive markers were EMA, SMA, desmin and CD34. STAT6 was negative in the cases tested. By RT-PCR for the most frequently observed fusions, an AHRR-NCOA2 fusion transcript was found in 9/14 cases. GTF2I-NCOA2 was not detected in the remaining cases (n = 3). RNA sequencing revealed three additional positive cases; two harbored a AHRR-NCOA2 fusion and one case a novel GAB1-ABL1 fusion. Two cases failed molecular analysis due to poor RNA quality. In conclusion, the AHRR-NCOA2 fusion is a frequent finding in soft tissue angiofibroma, while GTF2I-NCOA2 seems to be a rare genetic event. For the first time, we report a GAB1-ABL1 fusion in a soft tissue angiofibroma of a child. Nuclear expression of NCOA2 is not discriminating when compared with other spindle cell neoplasms.
Assuntos
Angiofibroma/genética , Coativador 2 de Receptor Nuclear/genética , Fusão Oncogênica/genética , Neoplasias de Tecidos Moles/genética , Adolescente , Adulto , Idoso , Angiofibroma/patologia , Antígenos CD34/genética , Antígenos CD34/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Criança , Feminino , Genes abl/genética , Fator 2 de Liberação do Nucleotídeo Guanina/genética , Humanos , Masculino , Pessoa de Meia-Idade , Coativador 2 de Receptor Nuclear/metabolismo , Proteínas Repressoras/genética , Fator de Transcrição STAT6/genética , Fator de Transcrição STAT6/metabolismo , Neoplasias de Tecidos Moles/patologiaRESUMO
UNLABELLED: Lipofibromatous hamartoma (LFH) is a benign tumour of nervous tissue that most commonly involves the median nerve. Only a few cases of LFH in the foot have been described. In these cases growth of bone and other tissue causing macrodactyly, a condition known as macrodystrophia lipomatosa, is often observed. Conservative treatment of LFH is usually preferred because of the potential loss of neurological function after surgery. Here we present a rare case of a 44-year old patient with LFH causing macrodactyly of the second ray of the left foot whose symptoms did not improve after conservative treatment. We describe the diagnostic process and the operative resection that was performed and show the follow-up results 5 years after surgery. All the symptoms experienced by our patient had disappeared. This case demonstrates that operative treatment of LFH in the foot is a viable option in patients with persistent symptoms following conservative treatment. LEVEL OF EVIDENCE: Level V.
