Congenital nevi versus metastatic melanoma in a newborn to a mother with malignant melanoma – diagnosis supported by sex chromosome analysis and Imaging Mass Spectrometry

Abstract

A 37-year-old pregnant woman presented with a 2-cm irregular reddish nodule on her left upper arm during pregnancy. A biopsy from the lesion showed a 2.2-mm thick malignant melanoma with intravascular invasion, 25 mitosis/mm(2) and no ulceration. Following induction of labor, the patient underwent re-excision with sentinel lymph node biopsy. This showed no residual melanoma and no lymph node metastasis. The newborn boy had multiple pigmented lesions on the trunk, some of which were large and irregular. Two were biopsied and histologic examination showed dense dermal proliferation of medium sized melanocytes with multiple mitotic figures and no maturation with their descent into the dermis, raising suspicion of transplacental metastases. Examination of the placenta failed to show metastatic lesions. Multiplex polymerase chain reaction (PCR)-based genotyping, including testing for amelogenin locus for sex chromosome determination, demonstrated the presence of Y chromosome material in the melanocytes of the newborn's lesions excluding maternal origin. A diagnosis of congenital nevi was rendered. Subsequently, Imaging Mass Spectrometric analysis of the mother's lesion showed proteomic signature expression indicative of malignant melanoma, whereas the two lesions in the newborn showed changes indicative of nevi. This case demonstrates the utility of genotyping and Mass Spectrometry analysis in this challenging clinical scenario.

Histopathology‐guided mass spectrometry differentiates benign nevi from malignant melanoma

“…In a subsequent study, HGMS analysis was performed on diagnostically challenging atypical spitzoid neoplasms and, when compared and correlated with the clinical behavior, mass spectrometric diagnosis showed stronger association with clinical outcome than did the histopathological diagnosis . The mass spectrometric algorithm was successfully applied in a challenging case of a baby born to a mother who developed melanoma during pregnancy . The baby was born with atypical melanocytic lesions on the trunk.…”

Mass Spectrometry Imaging Can Distinguish on a Proteomic Level Between Proliferative Nodules Within a Benign Congenital Nevus and Malignant Melanoma

“…(6) Subsequently, we studied a melanoma from a mother and two atypical pigmented lesions from her newborn baby by MSI to determine whether these were metastases or atypical nevi. (11) In the current case we used MSI to aid our diagnosis by distinguishing on a proteomic level between malignant melanoma and a nodular proliferation within a benign congenital nevus. In brief, 5μm-thick formalin-fixed, paraffin-embedded tissue sections were used after de-paraffinization.…”

What to Look Out for in a Newborn with Multiple Papulonodular Skin Lesions at Birth

“…Death typically occurs before the age of 3 months. Placental involvement appears to be a key risk factor among patients with no clinical evidence of metastasis at birth [21].…”