Array-based comparative genomic hybridization (aCGH) analysis is a useful tool for distinguishing primary pulmonary...

Distinguishing primary from metastatic disease is vital for patient prognosis and care. This becomes a difficult task for both clinicians and pathologists when the clinical data, morphology, and immunohistochemistry (IHC) are not congruent. Array-based comparative genomic hybridization (aCGH) is a fairly recent technique that enables the analysis of whole tumor genome for discreet genetic abnormalities. As it is applicable to paraffin-embedded tissue, it could be suited for surgical pathology settings. We report a case of a 71-year-old woman diagnosed with uterine carcinosarcoma associated with high-grade neuroendocrine carcinoma (NEC). Six months later, the patient presented with pulmonary nodules. A wedge resection of one the nodules was performed and the histology and IHC were consistent with NEC. However, the diagnostic dilemma was whether the pulmonary lesions were primary of the lung or metastatic from the NEC component of the endometrium. Clinical, morphologic, and IHC analysis were not helpful to answer the above question. However, by revealing different genetic profiles of each of the 2 tumors, aCGH was suggestive of the existence of 2 independent primary tumors one endometrial and second pulmonary. In conclusion, aCGH is a powerful tool that is capable of revealing tumor gene fingerprinting and it can be used in routine surgical pathology especially in those cases where the other conventional techniques are not helpful.