A lung nodule showing both adenocarcinoma and diffuse large lymphoma: a pathological anatomy surprise

Lymphoid cells and tissues are integral to the immune system, which is crucial in maintaining our body's defense against harmful pathogens. They form the building blocks of lymphoid organs, which include the spleen, thymus, and lymph nodes.
Lymphoid cells consist of various types of immune system cells. These include B and T lymphocytes, which are responsible for producing antibodies and killing infected cells, respectively. Dendritic cells act as messengers between the innate and adaptive...

Lymph nodes are bean-shaped structures that cluster along the lymphatic vessels in the inguinal, axillary, and cervical regions. Each node is divided into compartments by a capsule that extends trabeculae inward.
From a histological perspective, lymph nodes can be split into two main areas: the superficial cortex and the deep medulla. The outer cortex is populated by dendritic cells, macrophages, and B lymphocytes, which are densely packed into follicles. When these B-lymphocytes are presented...

Secondary organs, including lymph nodes, the spleen, and mucosa-associated lymphoid tissue (MALT), work harmoniously to protect us from disease and infection.
The spleen is a vital organ in the lymphatic system, nestled in the upper left side of the abdomen. It is composed of two primary regions: the red pulp and the white pulp, each having distinct functions. The red pulp performs a significant role in blood filtration. It efficiently purges the blood of old or damaged red blood cells and...