If you don't remember your password, you can reset it by entering your email address and clicking the Reset Password button. You will then receive an email that contains a secure link for resetting your password
If the address matches a valid account an email will be sent to __email__ with instructions for resetting your password
Department of Plastic and Reconstructive Surgery, St-Luc University Hospital (Brussels)—Catholic University of Louvain-10 av. Hippocrate, B-1200 Brussels, Belgium
Department of Plastic and Reconstructive Surgery, St-Luc University Hospital (Brussels)—Catholic University of Louvain-10 av. Hippocrate, B-1200 Brussels, Belgium
Department of Plastic and Reconstructive Surgery, St-Luc University Hospital (Brussels)—Catholic University of Louvain-10 av. Hippocrate, B-1200 Brussels, Belgium
Objective: To discuss the characteristics of proliferative nodules in giant congenital nævi. Methods: We report the case of a newborn referred for staged curettage of a giant congenital nævus. A nodule was discovered on his left flank. It was excised for analysis during the first treatment session during the second week of life. Results: The nodule was soft and looked like a lipoma. On optical microscopy however, there was a high cellular density and a high number of mitoses. Although the genetic analysis for melanoma antigens was reassuring, a firm nodule recurred a few days later. A second excision was performed at the fourth week. Surprisingly, on optical microscopy, the cellular density was much lower and there were no more atypias or mitoses; many neurotization foci were present. The natural history changed to spontaneous regression of the cellular activity. The diagnosis of proliferative nodule was made. Conclusion: Proliferative nodules in giant congenital nævi have specific clinical and histological characteristics. These should however be put into perspective. As demonstrated in this case, there can be an initial high mitotic activity within the nodule but this should not lead to the misdiagnosis of malignant melanoma. The spontaneous regression of cellular activity will allow the correct diagnosis to be made.
Giant congenital nævi (GCN) may be accompanied by proliferative nodules. These are lesions that have specific histological characteristics: high cellularity, absence of high-grade nuclear atypia, low mitotic rate, smooth transition between the cells in the nodule and the adjacent nævus cells.
We report the case of a proliferative nodule of an atypical type.
1. Case report
Our patient was a full term male with no significant family or personal history. On physical examination, he presented with a GCN of the bathing trunk type (Fig. 1) . He was referred for surgical treatment. Because of the size of the nævus, we decided to perform a staged early curettage following the Johnson principle.
The first curettage session was performed on the tenth day. At that time, a two-centimetre soft nodule was discovered by palpation on the left flank (Fig. 2) . This nodule was excised for analysis. At cross-section, we found yellowish tissue, which looked like a simple lipoma. Optical microscopy was however surprising. The nodule was located in the deep dermis and in the subcutaneous tissue (Fig. 3) . The limits of the nodule were well defined. Nevertheless, at higher magnification, there was no capsule. There was a blending between the cells of the nodule and the cells of the adjacent nævus (Fig. 4) . The cellularity was high (Fig. 5) . Cells showed round nuclei, pyknosis, some anisokaryosis and contour irregularities. The cells of the nodule were similar to those of the dermal nævus (Fig. 6) but with higher pleomorphism and a high number of mitoses.
Figure 2Two-centimetre soft nodule (arrow) discovered on the left flank of the baby.
To go further in the diagnosis, additional investigations were performed. Although some of the melanoma associated antigens were present (Melan-A; Tyrosinase; gp100-hmb45), the tumour was negative for MAGE genes 1, 3 and 10.
At the second curettage session performed at the fourth week of life, there was evidence of nodule recurrence. Its characteristics had changed. The nodule was indurated. On cross-section, we found a pearly dense tissue. On optical microscopy, the nodule was made up of connective tissue with a moderately dense population of nævus cells. There were many neurotization foci (Fig. 7) . At higher magnification, no more atypias or mitosis were observed (Fig. 8) . There was spontaneous regression of cellular activity within the nodule.
Figure 7Nodule at the 4th week of life: presence of neurotization foci (arrows)—H&E×32.
A study of large congenital melanocytic nevi and associated malignant melanomas: review of cases in the New York University Registry and the world literature.
At time of diagnosis, the patient is usually between 1 and 5 years of age (Table I) . The discovery of a nodule in a newborn with a GCN is thus of great concern. Biopsy should be obtained to get a precise histological diagnosis.
Previously described ‘proliferative nodules’ had specific well defined characteristics: papule or nodule present around birth; surface smooth or seldom ulcerated; slow or no growth; cells in nodule larger than in nævus; cells in nodule blend with surrounding benign nævus cells; low mitotic index; little or no inflammation and no necrosis.
Our case report demonstrates how difficult the exact identification of such proliferative lesions in a GCN can be. Histological patterns can be very confusing.
Indeed, at the second week of life, the lesion excised on the left flank of our young patient presented with all the signs of a malignant pigmented neoplasm: pigmented cells grouped in a nodular formation showing high cellularity, nuclear atypia, a slight degree of pleomorphism and a very high mitotic index. There was a high suspicion of malignant melanoma. However, no advancing edge was observed. The blending between the cells of the nodule and the normal adjacent nævus cells suggested a differentiation process rather than a true neoplasm. Therefore, the excised lesion was to be considered as a ‘proliferation’ nodule but still nothing could be predicted in terms of benignity or malignancy. The fact that melanoma associated antigens were present (Melan-A; Tyrosinase; gp100-hmb45) had no significance since the nodule was situated in the deep dermis; pigmented cells of the overlying nævocellular nævus could simply have contaminated the sample. But the fact that the expression of MAGE genes 1, 3 and 10 was negative could not eliminate the diagnosis of melanoma (Table II) .
The natural history of the nodule allowed us to arrive at a firm diagnosis. In spite of recurrence and alarming appearance, the histological pattern of the recurrent nodule had completely changed. There was a clear regression of cellular activity. This was demonstrated by the absence of mitoses and by the many neurotization foci seen on optic microscopy.
As demonstrated by this case, the previously described characteristics of proliferative nodules can be put into perspective. An initial high mitotic activity within the nodule should not be misdiagnosed as malignant melanoma. The cellular activity might spontaneously regress with time.
However, since no such lesions have to our knowledge been published in the literature and since the origin of ‘proliferative nodules’ is still unknown, patients with similar lesions require a long term follow-up to detect later malignant transformation.
3. Conclusion
The melanoma transformation rate of GCN usually described in the literature is high.
This could be partially explained by misdiagnosis of melanoma-like lesions such as the one described in our report. As we have seen, proliferative nodules can be of an atypical type showing an initial high mitotic index with later spontaneous regression. Therefore, parents should not be unnecessarily alarmed.
References
Elder D
Elenitsas R
Benign pigmented lesions and malignant melanoma.
in: Elder D Elenitsas R Jaworsky C Johnson Jr, B Lever's Histopathology of the Skin. 8th ed. Lippincott-Raven,
Philadelphia1997: 647-648
A study of large congenital melanocytic nevi and associated malignant melanomas: review of cases in the New York University Registry and the world literature.
☆Part of this paper has been presented at: XVIII International Pigment Cell Conference (IPCC), Hotel Zuiderduin, Egmond aan Zee—The Netherlands—9/13 September 2002, Satellite Meeting I—The congenital nævus: research and treatment (13 September 2002).
00090-0&id=gr1.jpg){kind=link}
00090-0&id=gr2.jpg){kind=link}
00090-0&id=gr3.jpg){kind=link}
00090-0&id=gr4.jpg){kind=link}
00090-0&id=gr5.jpg){kind=link}
00090-0&id=gr6.jpg){kind=link}
00090-0&id=gr7.jpg){kind=link}
00090-0&id=gr8.jpg){kind=link}