Case Report
A two-year-old boy with a fair complexion presented with multiple, light
brown macules, evenly distributed on the cheeks and the forehead (Fig.
1a-b). The family history was negative for skin diseases. According to
the mother, small macular lesions had appeared at the age of 9 months on
the left temple without any preceding inflammation. Subsequently, new
lesions developed, particularly after the summer. Differential diagnoses
included juvenile warts, freckles and urticaria pigmentosa. The Darier
sign was negative. Since the lesions were restricted to the face and
increased after environmental sun exposure also a diagnosis of xeroderma
pigmentosum (XP) was considered. However, genetic testing for a mutation
in the ERCC 3 gene was negative. Five months later the number of
lesions had increased and the macules had evolved into monomorphic flat
reddish brown papules. (Fig. 2a-b) The clinical presentation now
indicated a diagnosis of benign cephalic histiocytosis (BCH).
Confirmation of the clinical diagnosis by histopathology was not
possible, as the mother did not consent to a biopsy from the face, where
at that time the lesions were exclusively located. A complete blood
count, comprehensive blood chemistry and an abdominal ultrasound were
all unrevealing. In light of the benign nature of BCH and its propensity
for spontaneous resolution a watchful waiting approach was chosen.
At follow-up examinations 9 and 16 months later a few new lesions had
developed in the pelvic area and on the dorsal forearms and none of the
pre-existing lesions had regressed. Two and a half year later part of
the extracephalic lesions had completely disappeared and the lesions on
the head were fading (Fig. 3a-b).