Prepubertal unilateral fibrous hyperplasia of the labium majus - Report of eight cases and review of the literature

OBJECTIVE: To report and propose a consensus term for eight cases of a newly recognized, asymptomatic, rapidly growing unilateral labium majus mass without palpable borders in prepubertal girls, appearing to be temporally associated with the physiologic increase of adrenal hormones. METHODS: Histologic examination, special stains, and immunohistochernistry were performed on all cases. in our personal cases, electron microscopy and chromosomal analysis were also performed, together with pelvic magnetic resonance imaging (MRI), inguinal exploration, vaginoscopy with biopsies, and adrenal hormone levels. RESULTS: Of the eight cases, seven were Ashkenazi Jewish girls from the same area in New York City. The unilateral masses were asymptomatic, soft, without palpable borders. The overlying skin had a slightly tan peau d'orange surface. The masses could not be completely excised because they extended into the contiguous pelvic floor. Histologically, the masses were composed of bland hypocellular fibrous tissue extending into the deep subcutaneous tissue. The masses blended into the surrounding tissue and adjacent pelvic floor as shown by MRI preoperatively and postoperatively. Residual tissue did not progress after incomplete resection. CONCLUSION: These fibrous lesions develop in months at the time of physiologic increase in adrenal hormone secretion just before puberty and subsequently appear to stop growing. The surgeon should not attempt a complete removal but simply excise sufficient tissue for a reasonable cosmetic result and to confirm the diagnosis. The lesions reflect fibroblastic hyperplasia, which is possibly hormone-driven. The ethnic and geographic clustering of cases raises consideration of environmental exposures or genetic predisposition.