Primary mediastinal germ cell tumor evolving into an extramedullary acute megakaryoblastic leukemia causing cord compression

Incidentally discovered primary mediastinal germ cell tumor

Most germ cell tumors arise from the testicles and often are self-diagnosed. Extragonadal germ cell tumors are rare and vary greatly in their clinical presentations. This case report describes a 24-year-old man with an unusual presentation for an extragonadal germ cell tumor.

Acute myeloid leukemia following a primary mediastinal germ cell tumor

Introduction

There is a known association between primary mediastinal germ cell tumor (PMGCT) and hematologic malignancy that is not linked to treatment. They are exceptionally rare entities with a low morbidity and a poor prognosis.

Case presentation

An 11‐year‐old boy presented with an anterior mediastinal mass diagnosed as a malignant germ cell tumor on the basis of an excisional biopsy. He was found to have acute myeloid leukemia (AML) two years after the chemotherapy for his germ cell tumor. The clinical course was very aggressive with a survival time of only 1 week after diagnosis of AML associated with PMGCT.

Conclusion

AML associated with PMGCT needs to be diagnosed correctly. Relevant examinations should be carried out in patients with PMGCTs during and after chemotherapy, and long‐term follow‐up is still necessary to reduce the risk of morbidity and mortality.

Non-seminomatous mediastinal germ cell tumor and acute megakaryoblastic leukemia

The association between mediastinal germ cell tumors (MGCT) and acute megakaryoblastic (M7) leukemia has been known for many years. We hereby present this review to better characterize the coexistence of these entities as well as the salient features, the treatment options, and the overall prognosis. A search of PUBMED, Medline, and EMBASE databases via OVID engine for primary articles and case reports under keywords "germ cell tumors" and "acute myeloid leukemia" revealed a total of 26 cases in English that reported MGCT and M7 leukemia. The median age at diagnosis of MGCT was 24 (13-36) years. All cases were stage III. All cases of MGCT were of non-seminomatous origin and one case was unclassified. MGCT occurred prior to the diagnosis of leukemia in 46% of cases and concomitantly in 31% of cases. M7 leukemia was never reported prior to the appearance of MGCT. Complex cytogenetics and hyperdiploidy were the most commonly reported cytogenetic abnormalities. In the 23 cases where the treatment regimen was available, platinum-based chemotherapy directed towards management of the germ cell tumors was used initially in 21 cases and leukemia-directed treatment was used initially in 2 cases only. The median time from diagnosis of MGCT to development of M7 leukemia was 5 (2.25-39) months. Median time to death from the initial diagnosis of MGCT was 6 (0.5-60) months. Patients with a history of MGCT are at higher risk of developing M7 leukemia. They need long-term follow-up with a particular attention to the development of hematological malignancies. The overall prognosis remains poor.

Development of acute megakaryoblastic leukemia with isochromosome (12p) after a primary mediastinal germ cell tumor in Korea

The association of hematological malignancies with a mediastinal germ cell tumor (GCT) is very rare. We report one case of a young adult male with primary mediastinal GCT who subsequently developed acute megakaryoblastic leukemia involving isochromosome (12p). A 25-yr-old man had been diagnosed with a mediastinal GCT and underwent surgical resection and adjuvant chemotherapy. At 1 week after the last cycle of chemotherapy, his peripheral blood showed leukocytosis with blasts. A bone marrow study confirmed the acute megakaryoblastic leukemia. A cytogenetic study revealed a complex karyotype with i(12p). Although additional chemotherapy was administered, the patient could not attain remission and died of septic shock. This case was definitely distinct from therapy-related secondary leukemia in terms of clinical, morphologic, and cytogenetic features. To our knowledge, this is the first case report of a patient with mediastinal GCT subsequently developing acute megakaryoblastic leukemia involving i(12p) in Korea.