[Infantile fibrosarcoma mimicking rapidly involuting congenital haemangioma (RICH)]

While haemangioma is common, an unusual appearance or course should alert the clinician's concern. Congenital haemangioma, particularly rapidly involuting congenital haemangioma (RICH), may carry a risk of misdiagnosis as congenital malignant tumours such as infantile fibrosarcoma (also known as congenital infantile fibrosarcoma). In this case, histological diagnosis may prove inconclusive, as in the case reported herein.

At birth, a newborn baby presented angiomatous lesions on the sole of the left foot that was initially considered as congenital haemangioma. Histopathological examination suggested highly remodelled immature infantile haemangioma. After surgery, the tumour increased in size within eight weeks. Reanalysis of the histology slides resulted in a diagnosis of infantile fibrosarcoma. This diagnosis was confirmed by the presence of a specific translocation seen in infantile fibrosarcoma (ETV6/NTRK3).

There is a risk of erroneous diagnosis in newborn infants between angiomatous tumour in RICH and malignant congenital tumours (particularly infantile fibrosarcoma). Clinicians should be attentive for this type of lesion and take all necessary diagnostic measures.