Normal or increased melanocyte numbers are found in the pigmented macules in both Peutz-Jeghers sy
In their letter Ayoub et al. suggest that Peutz-Jeghers Syndrome (PJS) can be distinguished from Laugier Hunziker Syndrome (LHS) by histological examination of the pigmented macules and suggest that the pigmented macules in PJS are histologically lentigos showing increased numbers of normal melanocytes whereas in LHS the histology shows no increase in melanocyte numbers. They support their argument with three references (Calnan, 1960; Dupre and Viraben, 1990; Ortonne, 1999).[2-4] Based on a wider assessment of the literature we do not believe that the histological findings in PJS and LHS are as distinct as Ayoub et al. suggest.
The following reports have shown no increase in melanocyte numbers in PJS. Yamada et al. reported three cases of PJS in which they had examined samples of the pigmented macules with both light and electron microscopy. They found pigmentation in the basal layer of the epidermis with no differences between the lesions and normal skin in the number of melanocytes. These findings were consistent at all sites studied which included the lip, fingers and toes. The dendrites of the melanocytes in the lesions were longer and more branched than those in normal skin.
Gregory and Ho in their review of the cutaneous manifestations of gastrointestinal disorders described the pigmented macules of PJS as showing increased melanin granules in the basal layer keratinocytes and dermis and either normal or increased numbers of melanocytes. Other articles have reported elevated numbers of melanocytes.[4,7] One is forced to conclude that in PJS there can either be normal or increased melanocytes in the pigmented macules compared with normal skin. In the case of LHS the majority of reports of LHS show normal melanocyte numbers on histology .[8,9] One report describes an increase in melanocyte numbers in LHS.(10)
In conclusion in both PJS and LHS there are reports of both normal and increased numbers of melanocytes within the pigmented macules. We therefore disagree with Ayoub et al and suggest that at present there is uncertainty about the nature of the histological appearances of PJS and LHS. Taken on their own the histological features are not diagnostic and over-reliance on histology in the diagnosis of these syndromes could lead to diagnostic error. We agree that genetic screening is not required routinely in all cases of suspected LHS. It is interesting to speculate that some of the confusion alluded to above arises from incorrect clinical diagnosis. In our patient the diagnosis was made clinically based on the late appearance of pigmentation, the history of negative GI investigation and on the clinical dermatological findings. Formal genetic screening was only performed at the request of the reviewers.
(1) Ayoub, N. M. (2003). Dissimilar histological features in Peutz- Jeghers syndrome and Laugier-Hunziker syndrome. Journal of Medical Genetics 40, e77.
(2) Calnan CD. The Peutz-Jeghers syndrome. Trans St John'sHosp Dermatol Soc 1960; 44: 58-64.
(3) Dupre, A., and Viraben, R. (1990). Laugier's disease. Dermatologica 181, 183-6.
(4) Ortonne, J. (1999). Les troubles de la pigmentation cutanee. In Dermatologie et maladies sexuellment transmissibles, G. E. Saurat JH, Laugier P, Lachapelle JM, ed. (Paris: Masson), pp. 407-426.
(5) Yamada, K., Matsukawa, A., Hori, Y., and Kukita, A. (1981). Ultrastructural studies on pigmented macules of Peutz-Jeghers syndrome. J Dermatol 8, 367-77.
(6) Gregory, B., and Ho, V. C. (1992). Cutaneous manifestations of gastrointestinal disorders. Part I. J Am Acad Dermatol 26, 153-66.
(7) McKee, P. Pathology of the skin, Second Edition (London: Mosby- Wolfe).
(8) Kemmett, D., Ellis, J., Spencer, M. J., and Hunter, J. A. (1990). The Laugier-Hunziker syndrome--a clinical review of six cases. Clin Exp Dermatol 15, 111-4.
(9) Veraldi, S., Cavicchini, S., Benelli, C., and Gasparini, G. (1991). Laugier-Hunziker syndrome: a clinical, histopathologic, and ultrastructural study of four cases and review of the literature. J Am Acad Dermatol 25, 632-6.
(10) Koch, S. E., LeBoit, P. E., and Odom, R. B. (1987). Laugier-Hunziker syndrome. J Am Acad Dermatol 16, 431-4.
(11) Lampe, A. K., Hampton, P. J., Woodford-Richens, K., Tomlinson, I., Lawrence, C. M., and Douglas, F. S. (2003). Laugier-Hunziker syndrome: an important differential diagnosis for Peutz-Jeghers syndrome. J Med Genet 40, e77.