The typical case of CALME is a prepubertal female (mean age: 7-8 years) that complains of bulging of unilateral labium majus. On physical examination, a painless and poorly defined unilateral labial enlargement is shown, which can extend to the mons pubis. Not overlying skin changes are shown and not cystic or solid mass is palpated.
The most accepted hypothesis concerning its pathophysiology is an asymmetrical physiologic growth of tissue with a hormonal response as the asymmetric female breast or male testis growth. However, the reason why only some girls develop CALME and the reason for the asymmetrical presentation is still unknown.
Ultrasonography (US) can be used as the first imaging approach, where a fat-containing ill-defined lesion can be shown. Magnetic Resonance Imaging (MRI) shows more accurately the extent of the lesion. Therefore, it could be reserved for cases in which vascular malformation o a mass is suspected.
US shows a heterogeneous labial enlargement without a definable mass or capsule, and MRI confirms ill-defined T1-weighted hypointense signal and T2-weighted hypo- to isointense to muscle signal with or without scattered feathery hyperintense linear septations. Ill-defined strands of enhancement following intravenous gadolinium-based contrast administration can also be seen. Fig. 1, Fig. 2,Fig. 3 and Fig. 4.
In the differential diagnoses, inflammatory causes, vascular anomalies, and neoplastic causes are included.
Concerning benign and focal lesions, low-flow vascular or lymphatic malformation, lipoma, and neurofibroma should be considered in CALME’s differential diagnosis. However, all these entities usually present as a definable cyst or mass, in contrast to the typical ill-defined swelling of CALME. Due to its fluctuating nature, inguinal hernia should be considered in the differential diagnosis of CALME. Bartholin’s duct cyst could be also included in the diagnosis study, but they are exceptional in pre-pubertal girls.
As regards to malignant focal lesions of the labium majus, rhabdomyosarcoma should be considered. As it happens with the benign lesions, a firm and palpable mass be seen in the physical examination.
In terms of less well-delimitated lesions, labial hypertrophy, vulvar edema, Crohn disease of the vulva, perineal nodular induration of cyclist and aggressive angiomyxoma should be excluded in the diagnosis of CALME.
Conservative approach is the accepted current treatment, as it may tend to resolve spontaneously and recur after surgical resection. It consists of close follow-up with physical and ultrasonography examinations every three months until puberty and can be continued annually after it.
Surgical resection should be reserved for patients in which vascular malformation or a mass is suspected or for cosmetic reasons.