Epithelioma of Malherbe: new ultrasound patterns

We retrieved 124 histologically Pilomatricoma cases: 28 patients with 32 lesions were preoperatively evaluated with ultrasound.22/32 have shown a solid formation, hypoechoic, with a sharp outline. Of these 22, 10 lesions were completely calcifying and 12 partially calcified. In 3/32 lesions with uncertain diagnosis, ultrasounds showed a complex/mixed pattern with pseudo-fluid areas and microspots. 7/32 lesions with US different diagnosis included 3 complex lesions, 2 cystic lesions and 2 solid nodular lesions.In addition to well-known ultrasound patterns (completely calcified and partially calcified) we identified three new, not yet described, patterns that constitute the 31% of the cases: complex, pseudocistyc and pseudotumoral.Calcifying Epithelioma of Malherbe - or Trichomatricoma, Pilomatricoma, Pilomatrixoma (PM) - is an uncommon tumour [1], with an incidence of 1/800-1000 cutaneous tumours and about 20 new reports per year [2,3], affecting predominantly women. It is more common at a young age, especially in the first two decades of life, with an onset below 10 years in 40% of cases [4,5]. Although multiple localizations have been described in literature [6,7], PM occurs as a solitary lesion on the face (47% of cases), neck [8] and upper trunk and can be associated to other diseases, e.g. Steinert's Myotonic Dystrophy and Gardner Syndrome [4,7,9,10].Recent studies have shown that recurrent activating mutations in the ss-catenina gene (CTNNB1), induce PM tumourigenesis through activation of the WNT signalling pathway [11,12]. Despite the benign biological behaviour of the majority of cases, the treatment is still surgical. However, in recent years, aggressive cases with local post-surgery recurrences or metastasis have been described [2,3,13,14], accounting for variable percentage rates in literature, with 6 cases out of 228 in the Forbis series [6]. According to some authors [13], local recurrences are related to tumour aggressiveness, while for others, these c