What histological feature distinguishes a poorly differentiated carcinoma?

A poorly differentiated carcinoma is characterized by a lack of specific cellular architecture. This means that the tumor cells show a high degree of variability and do not resemble the tissue of origin. In such tumors, the design and organization that one would typically expect in well-differentiated neoplasms are largely absent, leading to difficulties in identifying the tumor's original tissue type.

The presence of poorly defined and irregular cellular arrangements significantly contributes to the overall aggressive nature of these tumors, making them more challenging to diagnose and treat effectively. The histological pattern often appears disorganized, thus complicating the histopathological assessment and subsequent treatment planning.

While features such as a high mitotic rate and presence of necrosis may be observed in poorly differentiated carcinomas as well, these traits alone do not specifically distinguish them from other tumor types. Other options might demonstrate some level of cellular activity or change, but the defining characteristic remains the absence of a discernible architectural structure typical of well-differentiated cancers.