ARTICLE
Auteur(s) : Emmanuella
Guenova, Wolfram Hoetzenecker, Gisela Metzler, Martin Röcken,
Martin Schaller
Department of Dermatology, Eberhard Karl University – Tübingen,
Liebermeisterstr. 25, 72076 Tübingen, Germany
accepté le 17 Avril 2007
Porokeratosis represents a group of genetically heterogenous
disorders of keratinization, characterized by the histopathological
feature of the cornoid lamella, which represents a column of
tightly fitted parakeratotic cells with pyknotic basophilic nuclei
[1]. The multiple clinical variations of porokeratosis include
plaque type (Mibelli), disseminated actinic superficial
porokeratosis, porokeratosis palmoplantaris et disseminata,
porokeratosis punctata palmoplantaris, porokeratosis filiformis
palmoplantaris, giant porokeratosis and linear porokeratosis (LP)
[2-4]. The increased potential of porokeratosis to malignant
transformation is a well-known feature showing an association of
epithelial tumors (e.g. SCC, Bowen disease and basal cell
carcinoma) and porokeratosis between 7% and 11.6% [5, 6]. The
linear type possesses the highest malignant potential [7, 8]. In
this case we report of multicentric Bowen disease arising in
hyperkeratotic LP.
Case report
A 56-year-old man presented with a lifelong history of a scaly
linear lesion extending from the left buttock to the top of the
left foot. The lesion was not pruritic but had become irritated
over the past ten years – initially only around the ankle but now
in the gluteal region as well. Serous fluid and blood
intermittently stained his clothes, which stimulated him to seek
medical help. Occasional exposure to sun with no blistering sunburn
was recalled. The patient had no history of other skin diseases and
the family history revealed neither porokeratosis nor any cancer of
the skin.
Physical examination showed an extensive linear lesion lateral
on the left leg perfectly matching the lines of Blaschko. It
consisted of multiple, well-demarcated, confluent patches, several
cm in size with silvery scale and red-brown rim (figure 1A). Two eroded
plaques were noted within this larger lesion – a 10 × 12 cm
lesion over the left fifth metatarsal bone (figure 1B) and a 3 ×
3 cm one on the left buttock. The remaining clinical
examination showed no pathological findings.
Histological examination of a typical scaly lesion showed
prominent cornoid lamellae on a background of ortho- and
parahyperkeratosis and irregular acanthosis, confirming the
diagnosis of LP (figure
1C). Punch biopsies from the erosive plaques revealed an
abundance of atypical epithelial cells with hyperchromatic nuclei
and loss of polarity. The acanthotic epidermis showed a classic
“windblown appearance”, consistent with Bowen disease (figure 1D). A
computer-tomography scan of the thorax, abdomen and pelvis revealed
no pathological findings.
The two plaques of Bowen disease were completely excised and the
defects covered with split-thickness skin grafts taken from the
left thigh. The surgical procedure and the postoperative period
were uneventful. Follow-up at six months revealed no evidence of
recurrence.
Discussion
LP is a rare variant of porokeratosis caused by a clonal
proliferation of keratinocytes along the lines of Blaschko.
Occurrence of LP is usually sporadic with no definitive pattern of
inheritance established. However, LP has been observed concurrently
with disseminated superficial actinic porokeratosis (DSAP) [9-13].
Recently, Freyschmidt-Paul et al. and Boente et al. described 3
cases of LP associated with DSAP, which is known to have an
autosomal dominant trait [9, 10]. In general, as postulated by
Happle, two types of segmental manifestations of autosomal dominant
disorders can be distinguished [14]: type 1, which represents a
linear appearance in an otherwise healthy person and which can be
explained by postzygotic novel heterozygous mutation. Type 2
reflects loss of heterozygosity (LOH) for the same allele and
displays severe involvement due to homo/hemizygosity for the
underlying gene. As a characteristic feature, these patients show
severe linear manifestation along the lines of Blaschko (e.g. LP),
superimposed on a milder, nonsegmental, heterozygous involvement of
the some disorder (e.g. DSAP).
The patient described in this report stated a life-long history
of LP. This feature would be in line with LOH. However, as there
was no further pathological involvement of the patient’s skin
beside LP and family history revealed no evidence of porokeratosis,
we suggest a type 1 segmental manifestation.
In this case, multicentric Bowen carcinoma developed on the
background of a life-long LP. Interestingly, cancer-proneness of LP
may be explained by allelic loss [8]. Furthermore, investigations
have demonstrated an increased expression of the p53 tumor
suppressor gene in all types of porokeratosis, a prerequisite for
premalignant conditions [15, 16]. Malignant transformation has been
reported in all five clinical variants of porokeratosis, however
the rare linear type is particularly susceptible to carcinogenic
degeneration [6, 8]. Treatment options for porokeratosis include
topical 5-FU, retinoids and imiquimod [17, 18]. When malignant
change occurs, surgery is required and micrographic surgery offers
a precise way to separate the tumor from its porokeratotic
background.
We describe a case of multicentric Bowen disease, arising in a
lesion of hyperkeratotic LP, thus providing further evidence of the
increased oncogenic potential of LP. Patients with this variant of
porokeratosis should be monitored regularly to insure that
malignant changes are detected as soon as possible and to minimize
the risk of invasive and potentially metastatic tumors.
Acknowledgements
Financial support: none. Conflict of interest: none.
References
1 Wade TR, Ackerman AB. Cornoid lamellation. A histologic
reaction pattern. Am J Dermatopathol 1980; 2: 5-15.
2 Chernosky ME, Freeman RG. Disseminated superficial
actinic porokeratosis (DSAP). Arch Dermatol 1967; 96: 611-24.
3 Guss SB, Osbourn RA, Lutzner MA. Porokeratosis
plantaris, palmaris, et disseminata. A third type of porokeratosis.
Arch Dermatol 1971; 104: 366-73.
4 Guss SB. Porokeratosis. Arch Dermatol 1972; 105: 297.
5 Otsuka F, Someya T, Ishibashi Y. Porokeratosis
and malignant skin tumors. J Cancer Res Clin Oncol 1991; 117:
55-60.
6 Sasson M, Krain AD. Porokeratosis and cutaneous
malignancy. A review. Dermatol Surg 1996; 22: 339-42.
7 Otsuka F, Iwata M, Watanabe R, Chi HI,
Ishibashi Y. Porokeratosis: clinical and cellular
characterization of its cancer-prone nature. J Dermatol 1992; 19:
702-6.
8 Happle R. Cancer proneness of linear porokeratosis may be
explained by allelic loss. Dermatology 1997; 195: 20-5.
9 Boente MC, Lopez-Baro AM, Frontini M. V, Asial
RA. Linear porokeratosis associated with disseminated superficial
actinic porokeratosis: a new example of type II segmental
involvement. Pediatr Dermatol 2003; 20: 514-8.
10 Freyschmidt-Paul P, Hoffmann R, Konig A,
Happle R. Linear porokeratosis superimposed on disseminated
superficial actinic porokeratosis: report of two cases exemplifying
the concept of type 2 segmental manifestation of autosomal dominant
skin disorders. J Am Acad Dermatol 1999; 41: 644-7.
11 Lucker GP, Steijlen PM. The coexistence of linear
and giant porokeratosis associated with Bowen’s disease.
Dermatology 1994; 189: 78-80.
12 Commens CA, Shumack SP. Linear porokeratosis in two
families with disseminated superficial actinic porokeratosis.
Pediatr Dermatol 1987; 4: 209-14.
13 Welton WA. Linear porokeratosis in a family with DSAP.
Arch Dermatol 1972; 106: 263.
14 Happle R. Loss of heterozygosity in human skin. J Am
Acad Dermatol 1999; 41: 143-64.
15 Nelson C, Cowper S, Morgan M. p53, mdm-2, and
p21 waf-1 in the porokeratoses. Am J Dermatopathol 1999; 21:
420-5.
16 Magee JW, McCalmont TH, LeBoit PE.
Overexpression of p53 tumor suppressor protein in porokeratosis.
Arch Dermatol 1994; 130: 187-90.
17 Jensen JM, Egberts F, Proksch E,
Hauschild A. Disseminated porokeratosis palmaris and plantaris
treated with imiquimod cream to prevent malignancy. Acta Derm
Venereol 2005; 85: 550-1.
18 Goldman GD, Milstone LM. Generalized linear
porokeratosis treated with etretinate. Arch Dermatol 1995; 131:
496-7.
|
Printable version
Version PDF
