Uterine smooth muscle tumor of uncertain malignant potential (STUMP) with coagulative necrosis: a comprehensive clinicopathologic study of 10 cases with long-term follow up

To observe the importance of coagulative tumor cell necrosis (CTCN) in the diagnosis of uterine smooth muscle tumors and to find ancillary methods that could help identify cases with potential of recurrence. Ten cases were selected. Complete clinical dates and pathological findings were reviewed for each case. Immunohistochemical stains for p16, p53, DOG-1, CD117 and Ki-67 were performed. The follow-up data was all available. Large areas of geographical CTCN were noted in 3 cases and multiple small foci of CTCN were found in 7 cases. Cytological atypia was absent to mild. The highest mitosis was 5 MFs/10 HPFs. One case was treated with leuprolide acetate before operation. P16, P53 and DOG-1 that were negative in other cases were diffusely positive in this case which also had a higher proliferation index (Ki-67) than others. This case developed recurrence at 27 months after the initial operation. This study suggests that a minority of STUMPs with CTCN will recur latterly. The combined results of P16, p53 and Ki-67 stains are useful to identify the STUMPs with an increased risk of recurrence supporting earlier observations. DOG1 may be a useful marker for STUMPs with potential malignancy. Our study adds to the limited experience of the clinical behavior of uterine smooth muscle tumors with coagulative necrosis treated with Leuprolide acetate (GnRH agonist).