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SEER Inquiry System - Report
Produced: 01/16/2026 7:43 AM
Question 20110110
Inquiry Details
References:
2007 MP/H Rules
Question:
MP/H Rules/Multiple primaries--Head & Neck: If a 1991 neuroesthesioblastoma [9522/3] of the nasal cavity has subsequent recurrences of the same histology but later "recurs" in 2008 with "sarcoma, NOS, high grade" on a biopsy and a "high grade fibrosarcomatous transformation of esthesioneuroblastoma" [8810/3] on resection, should the subsequent tumor be reported as a new primary if the clinician continues to refer to the tumor as a "recurrence"? See Discussion.
Discussion:
Are histologic transformations always recurrences of the original tumor?
Answer:
Assuming the same primary site for the 2008 lesion, according to the current MP/H rules the high grade fibrosarcoma [8810/3] is a new primary per Head & Neck MPH rule 11 because it is a different histology.
The revised MP/H rules will include tables to define tumors that de-differentiate (transform) and recur with what is seemingly a different histology. Although the rules will be changed in the future, we must use the rules in place at this time for this case.
