Acta Dermato-Venereologica issue 50:1 98-1CompleteContent | Page 44

SHORT COMMUNICATION
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Clinical Characteristics of the Halo Phenomenon in Infants with Neurofibromatosis 1: A Case Series
Monji KOGA 1 , Yuichi YOSHIDA 2 and Shinichi IMAFUKU 1
Department of Dermatology, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, and 2 Department of
Medicine of Sensory and Motor Organs, Division of Dermatology, Faculty of Medicine, Tottori University, Tottori, Japan. E-mail: mob3mob3@
yahoo.co.jp
1
Accepted Sep 13, 2017, Epub ahead of print Sep 13, 2017
Although 95% of patients with neurofibromatosis 1 (NF1)
can be diagnosed by the age of 8 years using National In-
stitutes of Health criteria (1), diagnosis in infants without
a family history is sometimes difficult. Mutation analysis
has recently been reported to be useful for early diagnosis,
but it is often difficult to perform genetic diagnostics in
daily medical practice (2). The presence of multiple café
au lait macules (CALMs) on the entire body including
the back is the most common symptom of NF1 in infants.
Mongolian spots (congenital dermal melanocytosis) are
frequently seen on the back and buttocks of Asian infants
and generally disappear by adolescence (3–5); therefore,
CALMs often accompany Mongolian spots in Asian
infants with NF1. When CALMs are present within a
Mongolian spot on the back of such infants, the CALMs
are typically surrounded by a more lightly pigmented halo
(6). The characteristics of this peculiar phenomenon have
not been investigated in detail (7–10). We conducted a
case series study of infants with NF1 to reveal the clinical
characteristics of halo phenomenon.
MATERIALS AND METHODS
This study included 24 patients from among 95 children (age range
0–10 years) with NF1 who visited the Department of Dermatology
at Fukuoka University Hospital or Tottori University Hospital bet-
ween 2005 and 2016. All patients had 6 or more CALMs and fulfil-
led the NF1 diagnostic criteria proposed by the National Institutes
of Health (11). Some children did not fulfil the diagnostic criteria
of NF1 at the time of first presentation, but we confirmed that all
patients eventually fulfilled the criteria. The patients all had at least
one CALM overlapping with a Mongolian spot on the back or but-
tocks and their records included a photograph of the lesion. Genetic
screening tests were performed in 5 patients. Clinical information,
including sex, age, family history of NF1, was retrieved from
medical records. The number of CALMs within a Mongolian spot
was counted manually on clinical pictures. We also investigated
the colour tone of CALMs with and without the halo phenomenon
using digital clinical photographs and computer software. The
luminance of each CALM was quantified with Adobe Photoshop
software (Adobe Systems, San Jose, CA, USA). For individuals
with multiple CALM lesions, the luminance was averaged. A higher
luminance index indicated a brighter lesion, suggesting a lighter
coloured macule. The luminance of CALMs with and without
haloed phenomenon was compared using Student’s t-test; p < 0.05
was considered statistically significant. The study was approved by
the ethics committees of the institutional review boards of Fukuoka
University Hospital and Tottori University Hospital.
RESULTS
Summarized data from all patients with NF1 who had
macules overlapping a Mongolian spot are shown in Table
SI 1 . Twenty-four patients with NF1 were enrolled in this
study (9 boys, 15 girls; median age 7 months; range 0–91
months). Seven out of 21 patients (33.3%) had a family
history of NF1 confirmed from medical records. Four out
of 5 patients who underwent genetic testing had an NF1
gene mutation; in the fifth case, no obvious mutations
were found in NF1. Twenty-one out of 24 patients (87.5%)
had CALMS that showed the halo phenomenon. Among
them, 10 patients (41.6%) showed the halo phenomenon
around all CALMs within the Mongolian spot (Fig. 1a: re-
presentative case, F4). The remaining 11 patients (45.8%)
had CALMs both with and without the halo phenomenon
(Fig. 1b: representative case, F5). Three patients had
only one CALM overlapping a Mongolian spot and did
not show the halo phenomenon (Fig. 1c: representative
case, F13). Among a total of 102 CALMs overlapping
Mongolian spots in 24 patients, 69 (67.6%) showed the
halo phenomenon and 33 (32.3%) did not.
We focused on the 11 cases that had CALM lesions
both with and without the halo phenomenon (Table
SII 1 ). Macroscopically, we found that in most CALMs
with the halo phenomenon, not only the circumference
of the CALM, but also the CALM itself, was lighter in
colour than CALMs without haloes (Fig. 1b, d, e). Also,
CALMs with haloes had an indistinct edge compared
with CALMs without the phenomenon. When digitally
quantitated, the mean luminance index of CALMs with
the halo phenomenon was higher than that of CALMs
without the halo phenomenon. However, this difference
did not reach statistical significance (p = 0.44).
DISCUSSION
To our knowledge, this is the first case series study
focusing on this issue. First, we found that the halo
phenomenon was present in 21 of 24 patients with NF1
(87.5%). Approximately half of the patients had CALMs
both with and without haloes. We also found that this
phenomenon does not occur around all CALMs within a
Mongolian spot. Among all CALMs that overlapped with
a Mongolian spot, 32.3% (33/102) did not show the halo
phenomenon. In addition, 3 of the 24 patients (12.5%) had
a single CALM overlapping a Mongolian spot and these
did not show the halo phenomenon. This finding suggests
that the number of CALMs within a Mongolian spot might
be related to the development of the halo phenomenon.
https://www.medicaljournals.se/acta/content/abstract/10.2340/00015555-2796
1
This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta
Journal Compilation © 2018 Acta Dermato-Venereologica.
doi: 10.2340/00015555-2796
Acta Derm Venereol 2018; 98: 153–154