University of Pittsburgh Medical Center Diffuse Osseous Metastases from an Extra-adrenal Paraganglioma: A Rare Entity Presentation #: EE-09 University of Pittsburgh Medical Center Francisca Oyedeji, MD Marion Hughes, MD Vikas Agarwal, MD

Disclosures: None

Purpose: To describe a rare case of diffuse osseous metastases from an extra- adrenal paraganglioma

Case Report: 47 year old female with a history of familial paraganglioma. She has a history of bilateral carotid body paragangliomas status post surgical resection of the left- sided paraganglioma, followed by radiotherapy to the bilateral neck Right sided unresected carotid body paraganglioma was monitored with yearly surveillance imaging and has remained stable for several years She was found to have multifocal areas of abnormal uptake in the vertebral bodies on a Sestamibi examination during work up for hypercalcemia and elevated parathyroid hormone Whole body imaging reveals no additional paragangliomas

Imaging Findings CT Neck: Well-circumscribed, avidly enhancing lesion at right carotid bifurcation (yellow arrow). This has remained stable for many years. Note extensive treatment related changes of the left neck related to prior left paraganglioma resection and subsequent radiation treatment.

Imaging Findings Sagittal fused Tc 99-Sestamibi scan: Increased avidity within sclerotic lesions of the T3 and T6 vertebral bodies (white arrows). Focal area of increased uptake in the region of parathyroid is compatible with a hyperfunctioning parathyroid gland (red arrow).

Imaging Findings Sagittal reformatted image from an enhanced soft tissue neck CT: Sclerotic lesion involving the T3 vertebral body consistent with sclerotic metastasis (yellow arrow).

Imaging Findings MRI Thoracic Spine: (B) (C) MRI Thoracic Spine: Sagittal T1 (A), T2 (B) and post contrast T1 (C) images show several T1/T2 hypointense lesions (white arrows in A and B) scattered throughout the thoracic spine which enhance after contrast administration (yellow arrows).

Imaging Findings CT Guided Biopsy: Axial CT image with the patient in prone position shows 14.5G 12.5cm Bard® Ostycut® biopsy needle in the sclerotic lesion involving the T3 vertebral body using a right transpedicular approach.

Pathology Findings T 2X HE stain demonstrates hypertrophied bony trabecula (T). These findings confirm the bony sclerosis noted on CT. Courtesy of Geoffrey Murdoch, MD, PHD

Pathology Findings Medium power HE stain demonstrates replacement of the normal marrow elements by abnormal cellularity (black arrows). Courtesy of Geoffrey Murdoch, MD, PHD

Pathology Findings A B C HE (A), chromogranin (B), and synaptophysin (C) stains: Note the abnormal cellularity of the bone marrow within a background of desmoplastic reaction. While this appearance is not the classic “cell ball” architecture seen in paragangliomas, staining with neuroendocrine markers (B and C) are positive. Note the presence of macrophages on the HE stain (yellow arrows). Courtesy of Geoffrey Murdoch, MD, PHD

Final Diagnosis: Extra- adrenal paraganglioma with diffuse osseous metastases to multiple vertebral bodies

Metastatic Extra-Adrenal Paraganglioma Extra- adrenal paragangliomas are rare with local recurrence being the most common pattern of disease recurrence. Moreso, osseous metastases from an extra- adrenal paraganglioma are exceedingly rare There have only been 4 case reports in the literature The pattern of osseous metastases is variable with lytic lesions being the most common pattern noted radiographically Bruno Lázaro, Mônica Klemz. Malignant Paraganglioma with Osseous Metastasis: A Case Report. Arq Neuropsiquiatr 2003;61(2-B):463-467 Justin H. Tan, MD, Mahmood F. Mfee, MD. Malignant Paraganglioma Manifesting with Calvarial Metastases. Radiology, 2013, vol 268 Issue 3: (919-923).

Follow-Up: Despite the presence of diffuse osseous metastases, the patient remained asymptomatic She was referred to radiation oncology for further management with stereotactic radiosurgery Upon completion of radiation treatment, she was started on systemic chemotherapy

Summary: Osseous metastases from an extra- adrenal paraganglioma is an exceedingly rare entity with only a few cases described in the literature Despite the presence of diffuse osseous metastases, patients may remain largely asymptomatic, as in our case Nonetheless, osseous metastases may occur and neuroradiologists should be aware of this complication Say CC, Hori J, Spratt J. Chemodectoma with distant metastasis: case report and review of the literature. Am Surg 1973;39:333-341.