Mast cell distribution in mice.

A survey on the distribution of mast cells in mice was carried out. Mast cells were present in abundance in tongue and to a lesser extent in sciatic nerve. Fewer numbers of mast cells were seen in lymph nodes, e.g. cervical, pararenal and iliac. Mast cells were not common in mesenteric lymph nodes in contrast to rats. Mast cells appeared to be widely distributed in different organs, e.g. salivary gland, cervix, vagina, uterus, epididymides, skeletal, muscle, ovaries, prostate, seminal vesicles, harderian glands, skin, adipose tissue, preputial gland, tail, urinary bladder, trachea, thymus and gall bladder. Mast cells were very few in heart, liver, bone marrow and lungs and generally fewer than in rats. Mast cells were very rare in spleen and adrenals. Scattered individual mast cells were occasionally seen in submucosa and serosa of stomach, oesophagus, small and large intestine. Mast cells were not seen in kidney, pituitary, testes, bone, spinal cord, brain, optic nerve and eyes. In lymph nodes mast cells appeared mainly in medullary sinusoids. There was no clear evidence of a difference between numbers of mast cells in animals of different age or sex. There was evidence of increased numbers of mast cells in inflammatory lesions and in cases of malignant tumours such as lymphomas. Presence of mast cells is incidental and is not indicative of any abnormalities.