Cutaneous lupus erythematosus mimicking multiple keratoacanthomas

ARTICLE

Auteur(s) : Francesco Valenzano¹, Angelo Carbone¹, Clara De Simone¹, Teresa Sisto¹, Paolo Amerio², Guido Massi³

¹Department of Dermatology, Policlinico A. Gemelli, Università Cattolica del Sacro Cuore, Largo Gemelli 8, 00168 Rome, Italy
²Department of Dermatology, Gabriele D’Annunzio University, Chieti, Italy
³Department of Dermopathology, Catholic University of the Sacred Heart, Rome, Italy

In October 2006, a 45-year-old white female presented with multiple nodular lesions which arose four weeks before our observation, after summer sun exposure. Clinical examination showed numerous erythematous and verrucous nodules of approximately 1 cm in diameter, centred by a horn-filled crater. These lesions were diffused on the face, including the ears, neck, V-area of trunk, upper limbs and back of hands (figure 1A) and they appeared to be persistent. She did not report any acute reaction after sunlight exposure. Clinical features were suggestive for multiple keratoacanthomas. Histopathology of one of the lesions showed a crateriform squamous neoplasm with a mature keratine plug. At the base of the lesion, dyskeratotic cells and elastic fiber extrusion were evident as seen in bono fide keratoacanthoma. In the superficial dermis there was a lichenoid band infiltrate with intraepidermal exocytosis (figure 1B). Diagnosis of warts was excluded on the basis of the absence of the peculiar papillated architecture of viral warts and the absence of koilocytes and hyperplastic granular layers usually associated with these viral-induced entities. Her familial history was negative for multiple keratoacanthomas. Investigations performed to exclude myelo- and lymphoproliferative disorders, malignancies or immunodeficiency, which have, rarely, been described in association with acquired multiple eruptive keratoacanthomas, gave negative results. The patient refused any medical or surgical treatment and was lost at follow-up until February 2007, when she presented again. At that time some small, well-shaped, erythematous and slightly hyperkeratotic papules were evident on the patient’s neck, V-area of the trunk and shoulders, while the nodules diagnosed as keratoacanthomas 4 months before were unchanged. A biopsy of one of such lesion revealed features consistent for an interface dermatitis with basal layer vacuolar alteration and lymphocyte intraepidermal exocytosis. Although not specific, histological features were considered to be consistant with a diagnosis of lupus erythematosus (LE), which was confirmed by direct immunofluorescence (DIF) findings and immune serological abnormalities. DIF of a papule showed granular deposits of IgG, IgM and C3 at the dermoepidermal junction. Analogous findings were also observed on DIF of a keratoacanthoma-like lesion. Serum searches revealed ANAs at low titer (1:160) and an increased titer of anti-Ro(SS-A) antibodies (normal value < 25 IU/mL). La(SS-B) and dsDNA antibodies were negative. UV-sensitivity-testing was not performed because the patient denied consent. The first skin biopsy was consequently re-evaluted in the search of signs for LE but no specific criteria for LE were found. Oral treatment with hydroxychloroquine 200 mg twice daily was therefore started resulting in a progressive and full clearing of all the lesions, also including the keratoachantoma-like ones, in two months. The complete therapeutical response suggested a definitive diagnosis of hypertrophic lupus erythematosus for all the cutaneous lesions. A three month follow-up visit did not reveal any relapse.

It is well known that keratocanthomas and squamous cell carcinomas may arise on chronic lesions of cutaneous lupus erythematosus [1]. In addition some authors have reported keratoacanthoma-like lesions accompanying classical features of cutaneous lupus erythematosus [2-4] (table 1). In our case lupus erythematosus presented, as its first manifestation, with clinical and histologic lesions resembling keratoacanthomas. Therefore histopathology alone was not sufficient to distinguish features of atypical lupus erythematosus from those of keratoacanthomas. As recently reported in the literature, differential diagnosis on histological grounds between lupus erythematosus and squamous neoplasms can be very difficult, even for experienced dermopathologists, since both clinical and histological features can lead to a misinterpretation [5]. In conclusion, from a practical point of view, our report shows that in cases of multiple eruptive keratoacanthoma-like lesions, a diagnosis of cutaneous lupus erythematosus should also be considered.

Acknowledgements

References

2 Uitto J, Santa-Cruz DJ, Eisen AZ, Leone P. Verrucous lesions in patients with discoid lupus erythematosus. Br J Dermatol 1978; 98: 507-20.

3 Vassallo C, Brazzelli V, Ardigò M, Barbagallo T, Borroni G. Multiple, keratoacanthoma-like nodules on a 47-year-old man: a rare presentation of cutaneous lupus erythematosus. Int J Dermatol 2003; 42: 950.

4 Cristofoletti Daldon PE, Macero de Souza E, Cintra ML. Hypertrophic lupus erythematosus: a clinicopathological study of 14 cases. J Cutan Pathol 2003; 30: 443.

5 Zedek DC, Smith Jr. ET, Hitchcock MG, Feldman SR, Shelton BJ, White WL. Cutaneous lupus erythematosus simulating squamous neoplasia: the clinicopathologic conundrum and histopathologic pitfalls. J Am Acad Dermatol 2007; 56: 1013-20.