Sacrococcygeal Teratomas: Clinico-Pathological Characteristics and Isochromosome 12p Status
Grzegorz T Gurda, Christopher J VandenBussche, Raluca Yonescu, Sheila F Faraj, Enrico Munari, Nilda Gonzalez-Roibon, Denise Batista, George J Netto. Johns Hopkins Hospital, Baltimore, MD
Background: The biological behavior of teratomas is highly variable and morphologic features alone are insufficient to predict their clinical course. Prognostic factors that influence behavior include: patient sex, age, anatomic site, coincident neoplasm and cytogenetic abnormalities. Gonadal teratomas have been well-characterized. Testicular teratomas are associated with isochromosome 12p, i(12p), and are malignant regardless of maturation, whereas ovarian teratomas are i(12p) negative and clinically benign when mature. Clinical characteristics and i(12p) status in extragonadal sites such as sacrum and coccyx remain poorly understood.
Design: 17 cases of mature sacrococcygeal teratomas (12 prepubertal and 5 postpubertal) were identified from our surgical pathology archives (1990-2012). Clinical records and slides were reviewed to confirm original diagnoses. Gains in chromosome 12p including i(12p) status were assessed on representative FFPE sections using fluorescence in situ hybridization (FISH) with a probe for 12p12.1 derived from three contiguous BAC clones (PR11-444D3, RP11-778H2 and RP11-146L7) (BacPac Resources at CHORI, Oakland, CA), and a control probe (D12Z3) for 12 centromere (Abbott Molecular, Des Plaines, IL).
Results: The average tumor size was larger in postpubertal patients compared to prepubertal cases (12.3 vs 5cm; p<0.01). A significantly higher number of postpubertal cases were recurrences (80% vs 25%; p<0.01), but only prepubertal recurrences were managed with postoperative adjuvant chemotherapy. All tumors were negative for i(12p). 100% survival was documented in our cohort with a median follow up of 6 years.
|All||Postpubertal||Prepubertal||Significance (pre vs postpubertal)|
|Mean size (cm)||6.3±4.2||12.3±1.1||5.3±3.4||**|
|Recurrent||41% (7/17)||80% (4/5)||25% (3/12)||**|
|Adjuvant Chemotherapy||18% (3/17)||0% (0/5)||25% (3/12)||**|
|i(12p) FISH||0% (0/10)||0% (0/3)||0% (0/7)||ns|
|Survival||100% (17/17)||100% (5/5)||100% (12/12)||ns|