1. Incidental Finding of Basaloid Squamous Cell Carcinoma of the Thymus During Nuclear Stress Test Using Technetium (99mTc) Sestamibi:
Aref Obagi MD, Lance Berger MD, Michael P. Carson MD
Jersey Shore University Medical Center, Department of Medicine, Neptune NJ
LEARNING OBJECTVES
FIGURE 1: ANTERIOR MEDIASTINUM MASS
DISCUSSION
Diagnose incidentally detected thymus tumors in patients undergoing nuclear cardiac stress tests
Review epidemiology and prognosis of basaloid squamous cell carcinoma of the thymus.
Thymus tumors account for less than 1% of all tumors.
Basaloid SCC of the thymus is a very rare type of thymic carcinoma and usually originates from multilocular thymic cyst.
Most cases occur during the 5th decade, are discovered incidentally by routine chest X-ray or thoracotomy for unrelated causes, it affects males and females equally, and the size of the tumor ranges from 5 to 20 cm.
It’s considered a low grade malignancy, but 30% of cases are associated with metastasis to lungs and liver.
Our literature search regarding tumors detected via Tc99 scans revealed 5 reports of benign Thymoma and one case of invasive epithelial thymoma. The search identified only 36 cases of Basaloid SCC of the thymus worldwide, and none were diagnosed incidentally during a nuclear stress.
Treatment options depend on the size and the stage of tumor, but typically surgical removal for small size and low stage (stage I and II) and adjuvant therapy with chemotherapy and radiation for large size and high stage (stage III and VI
CASE PRESENTATION
A male in his 50’s with a history of inferior MI, 3 bare metal stents (BMS) in the right coronary artery placed 3 years ago
presented with a warning from his Angelmed device regarding possible ischemia.
Angelmed devices are subcutaneous devices that monitor the ECG pattern and alert the patients with a vibratory signal that they might be having active/silent ischemia.
PMH: 30 pack year tobacco history, active ETOH abuse (6-12 cans of beer/week)
MEDS: Aspirin 325 mg daily, varenecline/chantix 1 mg every 12 hours, metoprolol succinate 25 mg daily, pravastatin 20 mg QHS
He was admitted, had negative troponins x3, and unchanged ECG.
A persantine technetium (99mTc) sestamibi nuclear stress test showed an inferior wall fixed defect consistent with ischemia
The nuclear images detected an incidental mass with increased 99mTc uptake in the anterior mediastinum, raising concerns for malignancy (FIGURE 1)
Cardiac cath was delayed to evaluate the mass as he might require resection
CT scan of the chest revealed a right anterior mediastinal mass measuring 4.5 cm x 4.6 cm x 4.9 cm infiltrating the lung parenchyma
DISEASE COURSE
Biopsy of the mass (FIGURE 2) revealed poorly-differentiated basaloid squamous cell carcinoma (SCC) of the thymus.
PET scan showed a mass with a standardized uptake value (SUV) of 7.2 consistent with malignancy
He then underwent surgical removal of the thymus followed by radiation and chemotherapy with PAC regimen (Cisplatin, Doxorubicin and Cytoxan).
SUMMARY
We report what to our knowledge is the first case of Basaloid SCC of the thymus incidentally detected during a Tc99 Sestamibi scan ordered to evaluate a patient for suspected coronary artery disease.
FIGURE 2: BASALOID SCC of the Thymus
REFERENCES
Brown JG1, Familiari U, Papotti M, Rosai J. Am J Surg Pathol Aug;33(8): doi: /PAS.0b013e3181a2443b.
Tseng JC1, Hua CC, Tsai MF, Chang LC. Chang Gung Med J Feb;27(2):
Ayman A. Farag, MD,a and Fadi G. Hage, MD, FASH, FACCa. Nucl Cardiol 2015;22:786