PMC10382325_01
Chest positron emission tomography/computed tomography.
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Positron emission tomography CT (PET/CT) scan demonstrated hypermetabolic uptake in the lung mass (SUV of 14.1) and mild uptake in a few mediastinal and right hilar lymph nodes (Fig. 1).
Histopathologic findings of combined small cell lung carcinoma with a heterologous component of rhabdomyosarcoma (A) Cell block shows a small round blue cell tumor with scant cytoplasm and nuclear pleomorphism (hematoxylin and eosin (H&E) stain, x 400). Immunohistochemistry shows a subset of tumor cells express (B) weak TTF-1 and (C) INSM-1, and a subset express (D) myogenin (x 400). All tumor cells show complete loss of nuclear (E) p53 and (F) retinoblastoma (Rb) protein (x 200). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
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Microscopic sections and cytologic smear preparations showed a neoplasm composed of round cells with scant cytoplasm and nuclear pleomorphism with inconspicuous nucleoli (Fig. 2A). Immunohistochemical stains revealed that a subset of tumor cells expressed weak TTF-1 (Fig. 2B), focal cytokeratin CAM5.2, and were positive for neuroendocrine markers INSM-1 (Fig. 2C) and synaptophysin. Another population of tumor cells was strongly positive for myogenic markers desmin, myogenin (Fig. 2D) and MyoD1. All tumor cells showed complete loss of nuclear p53 and retinoblastoma (Rb) protein expression (Fig. 2E and F).
Chest computed tomography scan before and after four cycles of chemoradiation (A) Chest CT scan at diagnosis of combined SCLC revealed a 15.4 cm x 13.2 cm lobulated mass in the right lower lobe. (B) Repeat chest CT scan after four cycles of concurrent chemoradiation therapy showed decrease in size of the mass (10.5 cm x 6.3 cm).
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Following four cycles of therapy, repeat chest CT scan showed partial interval decrease in size of the lung mass (Fig. 3).