A Case of Malignant Melanoma Arising in Mediastinal Malignant Teratoma

Abstract

We report about a 14-year-old boy who presented with an anterior mediastinal mass that was diagnosed as malignant teratoma. Surgical resection was performed along with pre- and postoperative chemotherapy. Although elevated alpha-fetoprotein became negative, he experienced pain in his right hip joint 3 months after resection. Systematic evaluation revealed multiple locations of metastasis, and the pathological diagnosis based on bone biopsy was malignant melanoma originating from malignant teratoma, which rapidly progressed. He died 15 months after diagnosis of the original malignant teratoma. Diagnosing and treating malignant transformation of teratoma, including malignant melanoma, is difficult because it is very rare. To our knowledge, this is the second reported case of malignant melanoma arising from a mediastinum malignant teratoma, with both cases having a poor prognosis. In addition to the follow-up of tumor markers, systematic evaluation, including imaging, should be considered even after remission to monitor malignant transformation of teratoma. We expect to establish a successful therapy and improve mortality rate after more such cases are accumulated.

Malignant Melanoma Arising in a Primary Mediastinal Teratoma: Case Report of a Rare Phenomenon and Review of the Literature

“…We conducted a literature search in PubMed using the key words, "germ cell tumor" "melanoma," "malignant transformation," and "mediastinum," and found 5 cases of malignant melanoma arising in primary mediastinal GCT. [7][8][9][10][11] Only one of these cases reported multilineage malignant transformation, as was found in our case. The 5 case reports and their characteristics are summarized in Table 1.…”

“…Germ cell tumor with MST to melanoma is an exceedingly rare phenomenon and only recently reported. We conducted a literature search in PubMed using the key words, “germ cell tumor” “melanoma,” “malignant transformation,” and “mediastinum,” and found 5 cases of malignant melanoma arising in primary mediastinal GCT 7–11 . Only one of these cases reported multilineage malignant transformation, as was found in our case.…”

“…Based on our literature search, there are 5 cases that reported this type of transformation in mediastinal GCTs. [7][8][9][10][11]…”

“…Melanoma was only recently described as a malignant transformation arising in a mediastinal GCT. Based on our literature search, there are 5 cases that reported this type of transformation in mediastinal GCTs 7–11 …”

Spontaneous intrapleural rupture of mediastinal teratoma in child

“…They are mature in 80 to 88% and represent the most common benign type of tumors of embryonic origin 2 . In children, germ cell tumors (GCTs) account for approximately 25% of mediastinal tumors , including 60% of mature teratoma, 20% of mixed GCTs, and 20% of embryonal carcinoma 3 . Teratomas usually sit at the level of the antero-superior mediastinum and are often asymptomatic, which underestimates their real proportion 4 .…”