An Illustrated Glossary of Histological and Pathological Terms
is a type of chronic inﬂ ammation character-
ized by localized aggregates of macrophages called
Collectively, these collections of histiocytes are termed
lomatous inﬂ ammation is characteristic of certain bacterial infections, par-
, fungal infections with organisms like
, and many other disease processes. Granulomatous
inﬂ ammation may contain areas of necrosis, as in mycobacterial or fungal
infections (caseous necrosis), or may be noncaseating as in the granulomatous
This lymph node biopsy contains abundant noncaseating granulomas
in a patient with sarcoidosis.
represents the increase in the
, not size, of cells within an
organ or a tissue. Contrast this to
below in which the cell
number, increases. Hyperplasia and hypertrophy both may result in a larger
organ or tissue. Hyperplasia can be the result of hormonal stimulation, as seen
in hyperplasia of the endometrial cells of the uterus in response to estrogen
This is an endometrial biopsy showing hyperplasia of the glandular
endometrium. The glands are increased in number and are abnormally close
together. Endometrial hyperplasia is a risk factor for the development of adeno-
carcinoma of the endometrium.
is a compensatory mechanism by which the size of cells increases
because of various stimuli, resulting in the increase in the size of the correspond-
ing organ. Cardiac myocytes hypertrophy in response to increased workload
because of hypertension or valvular dysfunction. In systemic hypertension, as
the cardiac myocytes enlarge, the heart itself enlarges, producing left ventricular
hypertrophy with a thickened muscular wall.
This image of a hypertrophied cardiac myocyte in a patient with hyper-
tension shows an enlarged, hyperchromatic (deeply staining) nucleus, referred
to as a “
is an early reversible cell injury characterized by cellular
swelling due to perturbations in cellular membrane ion-pump function.
This kidney biopsy shows swollen tubular epithelial cells with cytoplas-
mic clearing due to edema.
refers to a pattern of nuclear change seen in irreversibly damaged
cells, similar to pyknosis (below), in which the nucleus breaks apart and frag-
This image shows a nucleus undergoing karyorrhexis (
) in a malig-