Auteur(s) : Kenji Yamagata, Tsuyoshi Mitsuishi, Seiji Kawana , Department of Dermatology, Nippon Medical School, 1-1-5, Sendagi, Bunkyou-ku, Tokyo, 113-8603, Japan. |
ARTICLE
Auteur(s) :, Kenji Yamagata, Tsuyoshi Mitsuishi*, Seiji
Kawana
Department of Dermatology, Nippon Medical School, 1-1-5,
Sendagi, Bunkyou-ku, Tokyo, 113-8603, Japan
accepté le 28 Juin 2004
Folliculosebaceous cystic hamartoma (FCH) is a rare cutaneous
hamartoma comprised of follicular, sebaceous and mesenchymal
elements. FCH was first described in 1991 by Kimura et al. [1]. FCH
usually occurs on the central part of the face, especially on the
nose [1]. Histopathologically, FCH can be distinguished from
sebaceous trichofolliculoma based on its characteristic structures.
In this report, we describe a further variant case of FCH with hair
shaft fragments of the cyst presenting on the left ear in a
57-year-old Japanese male.
Case report
A 57-year-old Japanese male was referred to our hospital for an
asymptomatic skin lesion on his left ear. He had noticed the lesion
one year previously. On clinical examination, a skin-colored,
dome-shaped, hard nodule was found on the antitragus of his left
ear ( (figure 1) ). The
lesion was surgically removed under local anesthesia. Histological
examination revealed a large infundibular cystic structure lined by
stratified squamous epithelium in the middle of the dermis. The
epidermis was almost intact and was not attached to the cystic
structure. The cystlike structure contained laminated
orthokeratotic keratin and several hair shaft fragments. Numerous
mature sebaceous lobules were attached to this cyst-like structure
though sebaceous ducts and rudimentary hair follicles were also
present in its wall. This folliculosebaceous unit was surrounded by
dense fibrillary bundles of collagen in concert with numerous
capillaries and venules, and was separated from them by prominent
clefts ( (figure 2 )A,B).
Discussion
Folliculosebaceous cystic hamartoma (FCH) is a distinct type of
cutaneous hamartoma which is formed from stromal and epithelial
elements. The histological criteria of FCH as proposed by Kimura et
al. [1] were described in 1991. Our case conforms to the distinct
histological criteria of FCH. To date, 24 cases of FCH have been
reported. Although genital and multiple lesions occasionally occur
[2], most of the cases have been located on the face as a solitary
lesion [1]. Nine of 24 (37.5%) of those cases were found on the
nose, while only 2 cases (8.3%) were found on the ear [3]. The
duration of the lesion varied from 1 year to 24 years. They ranged
in size from 0.4 × 0.4 to 7.0 × 4.5 cm. The histological
differential diagnosis includes sebaceous trichofolliculoma (STF).
STF is also an adnexal tumor which is considered to be a variant of
trichofolliculoma [4]. Histologically, STF mimics FCH closely,
because STF exhibits a large central, epithelial-lined cavity or
sinus, radiating numerous sebaceous follicles. The differences
between FCH and STF are as follows; in STF, widely dilated sinus
tracts communicate directly with the surface epithelium, and no
obvious mesenchymal changes are seen as they are certainly seen in
FCH [1]. As a rare feature of FCH, some histological variants have
appeared in some reports, e.g., the existence of stromal
alterations and/or epithelial differentiation [5, 6]. Our case is
of interest from two points of view compared with other cases.
Firstly, the histological features of our case are typical but
present with hair shaft fragments within the cystic structure. Our
case is considered as a rare variant of FCH which developed to hair
follicle differentiation. Secondly, the location of the lesion
seems to be exceptional.
References
1 Kimura T, Miyazaki H, Aoyagi T, Ackermann AB.
Folliculosebaceous cystic hamartoma: A distinctive malformation of
the skin. Am J Dermatopathol 1991; 13: 213-20.
2 Bologina JL, Longley. Genital variant of
folliculosebaceous cystic hamartoma. Dermatology 1998; 197:
258-60.
3 Toritsugi M, Yamamoto T, Nishioka K.
Folliculosebaceous cystic hamartoma. Pract Dermatol 2002: 281-4;
(in Japanese).
4 Plewig G. Sebaceous trichofolliculoma. J Cutan Pathol
1980; 7: 394-403.
5 Fogt F, Tahan SR. Cutaneous hamartoma of adnexal and
mesenchyme: A variant of folliculosebaceous cystic hamartoma with
vascular-mesenchymal over growth. Am J Dermatopathol 1993; 15:
73-6.
6 Donati P, Balus L. Folliculosebaceous cystic
hamartoma: reported case with a neural component. Am J
Dermatopathol 1993; 15: 277-9.
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