Endocrine Abstracts

Introduction: Treatment options for acromegaly include surgery or radiation to remove or reduce the size of the tumor and medication to help normalize the hormone levels. While improving the prognosis, patients with acromegaly treated with radiotherapy are at risk of long-term development of secondary malignancies (1-2% at 10-20 years). We report the case of a 55-year old woman diagnosed with high-grade sarcoma of the sphenoid sinus developed 34 years after receiving 60Cobalt external beam radiation therapy for acromegaly.

Case report: The patient was diagnosed with acromegaly from a pituitary macroadenoma at 18 years (1986) and underwent 60Cobalt high voltage fractionated sellar irradiation in 1989 (total dose 6000 r), after which she was treated with Bromocriptine from 1989 to 2014 or a combination of Bromocriptine and Sandostatin LAR from 1998 to 2008. Apart from the modest and stable clinical picture of acromegaly she was asymptomatic, with a slowly decreasing pituitary mass (1.7 to 1.2 cm), but persistently elevated IGF1 levels (1.5 – 1.7 × ULN). In October 2023 she presented for a recent evidence of asymptomatic tumor increase, without hypopituitarism: a sellar mass of 3/3/1.9 cm, with large infrasellar extension, predominantly on the left side, involving the cavernous segments of the internal carotid arteries and apparently with a large extension into the sphenoidal sinus (Knosp 3b). IGF1 was 1.7×ULN. She began treatment with Lanreotide Autogel 120 mg monthly and underwent transsphenoidal surgery. Postsurgery she had a small residual tumor in the left cavernous sinus and stable GH hypersecretion (1.7×ULN) with central hypocortisolism. Histopathology revealed a high-grade (grade 3) sarcoma of the sphenoid sinus (leiomiosarcoma type). She was referred to an oncologist for radiation therapy but the treatment was postponed. A repeat MRI 2 months after surgery revealed a large invasive and erosive sellar and perisellar inhomogeneous mass (4.4/4.7/4.2 cm). The patient started stereotactic fractionated radiation therapy and was planned for chemotherapy.

Conclusion: Our case fulfills the diagnostic criteria of radiation-induced tumors: it occurred within the irradiated field, a sufficient latency period elapsed between irradiation and secondary tumor occurrence (>30 years) and the secondary tumor was proven to be of a different histological type from the original one. Clinicians should be vigilant about the possibility of post-radiation cranial sarcoma development (notably after conventional radiotherapy), suggested in this case by a tumor re-growth long-term after radiotherapy for acromegaly, not associated with a correspondent increase in hormonal activity.