Pregnancy and estrogen receptor beta expression in a large congenital nevus

Abstract

Background: Large congenital nevi carry a slightly increased risk of melanoma. Pregnancy poses an additional challenge in the monitoring of these patients because little is known regarding the effects of increased estrogen levels on congenital nevi.

Observations: A young woman was observed to have clinical lightening of her garment nevus and satellite nevi during 2 sequential pregnancies. Postpartum, the patient experienced darkening and repigmentation in her large garment nevus, with continued lightening of nearby satellite lesions. In addition to photographic documentation of these changes, biopsy samples taken during pregnant and nonpregnant periods underwent immunohistochemical evaluation for estrogen receptor beta (ERbeta), the predominant estrogen receptor in nevi and melanomas. Biopsy samples collected during pregnancy showed a decrease in nuclear staining for ERbeta compared with samples collected after pregnancy. These changes in ERbeta expression were not associated with histologic atypia during pregnancy or after delivery.

Conclusions: Congenital nevi may be unique in their response to altered estrogen levels. Given the slightly increased risk of melanoma in giant congenital nevi and the dearth of information available regarding the effects of pregnancy on congenital nevi, this case illustrates the need for further study of these pigmented lesions.

Fig. 1

Clinical Photographs: Note: Mild variation is seen in exposure secondary to different cameras used in the first photograph and the following photographs. A. Photograph of the patient’s lower extremities showing both the large garment nevus on right thigh/leg (arrow) as well as smaller satellite lesions taken at age 6, years prior to pregnancy. B. Photograph of the patient’s lower extremities, during her second pregnancy, demonstrating part of the large congenital nevus on the right thigh and leg (arrow) as well as smaller satellite nevi that had lightened during the pregnancy. Arrowhead depicts the location of the biopsy site for the immunostaining of Figures D, E. Circled areas depict the locations of all the biopsy sites taken at this time. C. Photograph of the patient’s lower extremities, one year post-partum, demonstrating darkening and re-pigmentation of the large garment nevus on the right leg (arrow), as well as a portion of the satellite lesion on the left thigh. Arrowhead depicts the site of focal darkening within the garment nevus and the biopsy site for the immunostaining in Figures F, G. Circled areas depict the location of all biopsy sites taken at this time. Immunohistochemistry: D. Immunohistochemistry for ERβ of the changing large congenital nevus taken from the patient’s right lower leg while 28 weeks pregnant (arrowhead in Figure B). The patient’s congenital nevus had exhibited clinical lightening throughout the pregnancy. This representative field shows a mixture of immunopositive (red) and immunonegative (blue) nevocytes for ERβ. Scale bar = 660μ E. Insert: Higher magnification of the same lesion showing numerous ERβ immunonegative nevocytes counterstained with hematoxylin (blue color). Scale bar = 164μ F. Immunohistochemistry for ERB within the darkening large congenital nevus taken from the patient’s right thigh one year following parturition (refer to arrowhead in Figure C). Note intense immunoreactivity for ERβ, particularly in the more rounded, clustered nevocytes. There is also significant cytoplasmic staining. Scale bar = 660μ G. Insert: Higher magnification with the same lesion. Virtually every nevocyte exhibits immunopositive staining for ERβ (red), with only rare exception. Scale bar = 164μ