Psoriasis is a chronic, immune-mediated polygenic skin disorder characterized by epidermal hyperplasia. Cardinal histopathological features are as follows: hyperkeratosis, parakeratosis, neutrophils in the stratum corneum and spinous layer, hypogranulosis with suprapapillary thinning, acanthosis, clubbed rete ridges, dilated capillaries, and perivascular lymphocytes. As histopathology may be more definitive compared to clinical manifestations, being able to diagnose psoriasis accurately through histopathology may enable early diagnosis and treatment. This could ideally mean a decrease in its progression, prevention of complications, and improvement of quality of life for psoriatic persons.

To examine, grade, and compare histopathologic f indings of psoriatic lesions with established parameters from previous literature.

This is a retrospective descriptive study that will examine, grade, and compare all histopathologic findings of psoriatic lesions of patients who have accessed care at Ospital ng Manila Medical Center from 2010-2015 with established parameters from previous literature.

All 41 cases (100%) showed parakeratosis, followed in decreasing order by 19 cases (46.34%) with Munro's microabscesses, 15 cases (36.59%) with pustules of Koga, 15 cases (36.59%) with hypogranulosis, and 11 cases (26.83%) with spongiosis. Using the visual analogue scale of Moorchung Net al (2013), 28 cases (68.29%) showed mild inflammatory infiltrates, followed in decreasing order by 19 cases (46.34%) with mild epidermal hyperplasia, 12 cases (29.27%) with mild capillary proliferation, and 4 cases (9.77%) with mild suprapapillary thinning.

Findings of the current study showed histopathologic features of both early and fully developed lesions based on established psoriasis histopathological parameters. Recognized histopathological features were not consistently found in well-developed lesions.