In small cell carcinoma of lung, blood vessels in necrotic area may show smudged hematoxophilic material in their walls, which represents DNA released from tumour cells. This is referred to as-

Ref:Robbins Basic Pathology (9th Edition), page no.508 Small cell lung carcinomas (SCLCs) generally appear as pale gray, centrally located masses with extension into the lung parenchyma and early involvement of the hilar and mediastinal nodes. These cancers are composed of tumor cells with a round to fusiform shape, scant cytoplasm, and finely granular chromatin. Mitotic figures frequently are seen.Small cell carcinoma with small deeply basophilic cells and areas of necrosis . basophilic staining of vascular walls due to encrustation by DNA from necrotic tumor cells (Azzopardi effect).Despite the appellation of small, the neoplastic cells are usually twice the size of resting lymphocytes. Necrosis is invariably present and may be extensive. The tumor cells are markedly fragile and often show fragmentation and "crush aifact" in small biopsy specimens. Another feature of small cell carcinomas, best appreciated in cytologic specimens, is nuclear molding resulting from close apposition of tumor cells that have scant cytoplasm. These tumors often express a variety of neuroendocrine markers in addition to secreting a host of polypeptide hormones that may result in paraneoplastic syndromes .