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Produced: 01/29/2026 10:55 PM
Question 20160073
Inquiry Details
References:
Subject matter expert
Question:
MP/H Rules/Multiple primaries/Histology: What histology and how many primaries are coded for a mixed germ cell tumor with a somatic type malignancy (rhabdomysarcoma) if the patient was diagnosed with seminoma of the testis in 2009 followed by a 2015 metastatic germ cell tumor in a retroperitoneal lymph node, stated to be a recurrence of the testicular cancer? See Discussion.
Discussion:
In September 2009 the patient was diagnosed with seminoma, classical type, following an orchiectomy. Testicular mass recurrence in 2014 was treated with chemotherapy.
Then in April 2015 a retroperitoneal dissection of a peri-aortic LN was positive for mixed germ cell tumor with somatic type malignancy (rhabdomyosarcoma) involving 1/11 nodes. Path Comment: major component of tumor is teratoma, rhabdomyosarcoma represents <5% of mass.
Now in October 2016, the patient has a retroperitoneal mass biopsy positive for spindle cell sarcoma with rhabdomyosarcomatous differentiation. The comment section of the pathology report states, "Given the history of a germ cell tumor w/ rhadbomosarcomatous component, the findings are consistent with a recurrence of rhabdomyosarcomatous component of germ cell tumor."
Can a seminoma transform to a mixed germ cell tumor with a somatic type malignancy (see SINQ 20140082 - testicular teratoma with somatic type malignancy)?
Answer:
According to our expert pathologist consultant, yes, seminoma could transform to a mixed germ cell tumor with a somatic type malignancy. He advises us to code this case as 9061/3.
From our expert pathologist consultant: This occurs as "reprogramming" of the initial germ cell tumor/seminoma cell. The process is not understood, but genetic studies support this progression concept. Most often the next step is teratoma. It is out of the teratoma that the somatic malignancy usually comes. I do wonder about the possibility that this was really an embryonal carcinoma which resembles a seminoma - occasionally this can be a difficult separation. I wonder if they radiated the scrotum following the orchiectomy, also, given the scrotal recurrence.
