Somatic malignant transformation in a sacrococcygeal teratoma in a child and the use of F18FDG PET imaging

Morphological spectrum and molecular features of somatic malignant transformation in germ cell tumours

AIMS

Somatic malignant transformation (SMT) arising in germ cell tumours (GCTs) is an infrequent, but clinically relevant event. There is only limited knowledge on the morphological spectrum of SMT, and therapeutic management of these patients is poorly defined. In this work we revisit two consecutive case series (n=756) of GCTs. Clinicopathological data of SMT arising in GCT were determined, with focus on the histopathological spectrum, and molecular aspects were obtained by Fluorescence in situ Hybridization (FISH) and Next Generation Sequencing (NGS).

METHODS AND RESULTS

30 male patients (28 primary testicular, 2 primary extragonadal) were included. These patients represent 4% of GCT patients diagnosed in two institutes (University Hospital Zurich and IPO Porto). The most common SMT were adenocarcinoma (n=8), embryonic-type neuroectodermal tumours (ENETs, n=8) and rhabdomyosarcoma (n=6), but a wide range of challenging morphologies were depicted, including low-grade neuroglial tumour, adenosquamous carcinoma, neuroblastoma and neuroendocrine carcinoma. SMT was found in 15 primary tumour samples and in 27 metastatic samples of these 30 patients, the latter showing poorer overall-survival. Adenocarcinoma occurred only in metastasis post-chemotherapy and in one primary retroperitoneal GCT with SMT, but not in GCT of the testis. 12p gains were identified by FISH in all cases. NGS results were available in 6 patients. Clinical trials and/or targeted treatments based on the molecular profile of SMT were recommended in 4 patients.

CONCLUSIONS

SMT arising in GCTs represents a diagnostic challenge and should be confirmed by a specialized uropathologist. NGS based treatment recommendations may improve outcome of these patients.

Neuroblastoma arising from an unresected sacrococcygeal teratoma in a child

Malignant transformation of a germ cell tumor, referring to the occurrence of somatic, nongerm cell malignancy within a germ cell tumor is a rare entity. The authors report a case of malignant transformation of an unreseceted sacrococcygeal teratoma to neuroblastoma in a 6-year-old girl and discuss this case in the light of relevant literature. This case shows that complete resection of germ cell tumor is necessary to prevent malignant transformation. In addition, when malignant transformation occurs, the treatment strategy must include surgery together with histology adapted systemic chemotherapy.

Long-term outcomes of surgery for malignant sacrococcygeal teratoma: 20-year experience of a regional UK centre

BACKGROUND

The timing of surgery for malignant sacrococcygeal teratoma is controversial. The long-term outcomes and complications of surgery for this rare tumour are presented.

METHODS

All cases of malignant sacrococcygeal teratoma in the 20-year period 1987-2006 were identified and the case notes retrieved. The age at diagnosis, investigations, presentation, type of surgery, early complications, recurrence rates, long-term complications and outcomes were recorded.

RESULTS

Twelve patients (three males, nine females) were identified. Mean age at presentation was 20.8 months (range: 12-39 months). All had the Carboplatin-Etoposide-Bleomycin chemotherapeutic protocol. The average time of follow-up was 10.6 years (range: 1-17 years). Ten patients had excision of their tumours following chemotherapy, whilst two patients had excision prior to chemotherapy. Two patients had recurrence of their tumours. There was one death (8%), which was due to disseminated metastasis. The other 11 children were all well at the last follow-up.

CONCLUSION

Surgery for malignant sacrococcygeal teratoma is safe and has a low complication rate. The long-term outcomes are favourable with minimal side effects.

Early experience with PET/CT scan in the evaluation of pediatric abdominal neoplasms

PURPOSE

Positron emission tomography/computerized tomography (PET/CT) scan provides both functional and anatomical information in a single diagnostic test. It has the potential to be a valuable tool in the evaluation of pediatric abdominal tumors. The goal of this study is to report our early experience with this technology.

METHODS

Children who underwent PET/CT scan in the workup for abdominal neoplasms between July 2005 and January 2008 were identified. Retrospective review of all radiologic studies, operative notes, and pathologic reports was undertaken.

RESULTS

A total of 36 patients were collected. These included Burkitt's lymphoma (8), neuroblastoma (7), rhabdomyosarcoma (6), ovarian tumor (3), Wilms' tumor (2), hepatocellular carcinoma (2), paraganglioma (1), germ cell tumor (1), undifferentiated sarcoma (1), renal primitive neuroectodermal tumor (1), gastrointestinal stromal tumor (1), adrenocortical carcinoma (1), inflammatory pseudotumor (1), and adrenal adenoma (1). All neoplasms were fluorodeoxyglucose (FDG) were avid. Our experience identified several potential uses for PET/CT scan in this group of patients. These include (1) preoperative staging, (2) selection of appropriate site for biopsy, (3) identification of occult metastatic disease, (4) follow-up for residual or recurrent disease, and (5) assessment of response to chemotherapy. It can also be valuable when the standard diagnostic studies are equivocal or conflicting.

CONCLUSIONS

Preliminary data indicate that PET/CT is a promising tool in the evaluation of pediatric abdominal malignancies. The delineation of the exact role of this diagnostic modality will require additional experience.