Discussion
UPS is a diagnosis of exclusion reserved for sarcomas with a distinct
combination of immunohistochemical and microscopic features, made only
after careful consideration of other differential diagnoses. This case
is unique both for being localized to the gastrointestinal tract, with
only 14 cases reported of cecal or ascending colon UPS, as well as the
young age of the patient. Only 2 other cases of gastrointestinal UPS
have been reported in the pediatric population12, 13.
This patient developed a non-obstructing right sided colonic mass, with
systemic features of disease including elevated inflammatory markers,
anemia, and weight loss, which are consistent with the presentation of
UPS. In spite of the tumor’s large size at diagnosis (7cm), the
tumor was excised with clear margins, no positive lymph nodes, and no
signs of metastasis. A lung lesion that was initially suspicious was
resected and found to be Histoplasmosis.
Chemotherapy was not given in this case as the tumor was resected with
clear margins and there was no lymph node involvement or metastatic
disease. She will be followed by oncology to monitor for recurrence
through periodic imaging and labs. Additional research into the role of
radiation and chemotherapy for abdominal UPS is needed, especially for
cases where surgical resection is not possible. Continued monitoring and
close follow-up are essential to a good long term outcome due to a
relatively high recurrence rate.
Conflict of Interest statement: no conflicts of interest
reported.