MRI has characteristic features distinguishing PVNS, mainly the presence of
hemosiderin deposition, especially through gradient-echo pulse.
(c) Corresponding susceptibility-weighted image demonstrates ill-defined areas of
hemosiderin deposition in the left fronto parietal region representing areas of hemorrhage.
As the injury evolves, red blood cell lysis and hematoma resolution occur with
hemosiderin deposition.
The lesions tend to bleed, causing
hemosiderin deposition and characteristic low signal intensity with all pulse sequences.
Stroma was vascular and made up of numerous dilated blood vessels; a large thrombus was noted in the centre with
hemosiderin pigmentation (Figure 2b).
Histologically, PVNS reveals a hypertrophic synovial process that is characterized by villous, nodular, or villonodular proliferation and
hemosiderin pigmentation.
Caption: Figure 3: (a) Plenty of endometrial gland and stroma (x10), (b)
hemosiderin laden of macrophages (x10)
Shows fibrous stroma with numerous
hemosiderin laden macrophages.
Dermis shows villous hair follicle with sebaceous gland hyperplasia with peri-infundibular infiltrate of lymphocytes and plasma cells with dilated capillaries and extravasation of
hemosiderin.
Pseudomelanosis occurs due to deposition of pigments like iron or
hemosiderin in the histiocytes.
Otherwise, hemorrhagic alterations and
hemosiderin pigment were present (Figure 3).