PMC5750482_01
An initial diagnostic SPECT/CT scan was performed 24 hours after administration of 5.3 mCi of Iodine-123. There is uptake in the left, posterior thyroid bed and anteriorly at the level of the hyoid bone. Physiologic uptake was noted in the salivary glands, nasopharyngeal mucosa, and gastrointestinal tract. A large (8 cm x 9 cm x 8 cm) heterogeneous left anterior mediastinal mass with mixed solid and cystic architecture was noted. This mass did not demonstrate uptake of the Iodine-123 tracer ((a), (b)). Posttreatment SPECT/CT one week later showed uptake of radioactive iodine by the mediastinal mass ((c), (d)).
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This mass did not demonstrate uptake of the I-123 tracer (Figures 1(a) and 1(b)). Posttreatment SPECT/CT one week later showed uptake of radioactive iodine by the mediastinal mass (Figures 1(c) and 1(d)).
Surgical pathology sections of 9.0 cm multilocular thymic cyst. (a) Cyst walls lined by simple low-cuboidal epithelium. (b) Cyst wall lined by simple columnar mucinous epithelium with goblet cells. (c) Fibrous stroma with glandular elements and numerous hemosiderin-laden macrophages. (d) Remnant of normal involuting thymic tissue adjacent to cystic spaces.
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Surgical pathology sections demonstrated a multiloculated mass composed of cystic spaces lined by a variety of epithelial types, including areas of low-cuboidal (Figure 2(a)), mucinous columnar with goblet cells (Figure 2(b)), ciliated columnar, and keratinizing stratified squamous epithelium. The intervening stroma was densely fibrotic with patchy chronic inflammation, glandular elements, and numerous hemosiderin-laden macrophages:providing evidence of previous hemorrhage (Figure 2(c)). Adjacent to the cystic spaces, there was a peripheral remnant of normal involuting thymic tissue showing Hassall corpuscles and associated lymphoid tissue (Figure 2(d)).