Two cases of Low-Grade adenosquamous carcinoma of breast arising within complex sclerosing lesions in females under 20 years of age

Abstract

Background and Aims Low-grade adenosquamous carcinoma (LGASC) of breast is a rare subtype of metaplastic carcinoma. An association with complex sclerosing lesions (CSL) has been described in older patients. 1,2 LGASC has not been previously reported in the literature in patients under the age of 20. We describe two cases of LGASC arising within large CSL in 18-year-old and a 19-year-old females. This study discusses the diagnostic difficulties and differential diagnoses of this entity, as well as the relationship between LGASC and CSL. Methods The two cases were received as part of the routine surgical workload at our laboratory. The slides were reviewed by multiple pathologists at our institution and both cases were referred to Prof. Ian Ellis for expert opinion. Results Immunohistochemistry features were consistent with LGASC. 3 The diagnoses were confirmed by Prof. Ellis. Discussion Although LGASC is classified as a variant of metaplastic carcinoma, it has a better prognosis with the principal risk being local recurrence. Thus distinction from benign entities, adequate excision and appropriate management is important, especially in young patients where treatment complications and cosmetic result are significant considerations. The pathogenesis of LGASC remains uncertain, however these cases add further evidence to the association between LGASC and CSL.