None of the above
Answer B) Medullary sinus
This migrant patient with weight loss, night sweats, a cough, and a positive interferon gamma assay most likely has active pulmonary tuberculosis, which is typically caused by Mycobacterium tuberculosis. M. tuberculosis, which is primarily ingested by macrophages, has sulfatides that prevent phagolysosomal fusion and can, therefore, persist in macrophages.
The medullary sinuses are vessel-like spaces between the cords of lymphatic tissue that are located in the medulla of a lymph node.
The medullary sinus is filled with macrophages and reticular cells.
Histiocytes, a form of macrophage in the medulla, span a network of pseudopods that filter the sinuses of incoming pathogens.
M. tuberculosis can, therefore, be seen within macrophages in the medullary sinus.