Nodular tenosynovitis (localized tenosynovial giant cell tumor) is benign lesion of the tendon sheath that may recur following an initial excision.
Factors associated with an increased risk of recurrence:
(1) simple enucleation or incomplete excision
(2) a high cellularity
(3) increased mitotic activity
The tumor usually has a partial rim of mature collagenous tissue, which may be mistaken for a capsule. Simple enucleation about the capsule often leaves a thin rim of tumor cells behind, which forms the basis for the recurrence.
Excision with a thin rim of normal tissue is usually adequate therapy. A persistently recurring tumor may require more extensive surgery.
