Pathology: desmoid fibromatosis

Infiltrative; long sweeping fascicles of spindle-stellate cells

Eosinophilic cytoplasm with long tapering processes

Ovoid nuclei with pinpoint nucleoli; occasional mitotic activity

Abundant collagenous matrix with prominent small vessels with perivascular oedema 

DNA-seq:  CTNNB1 mutation (c.121A>G; p.T41A)

Lobulated; spindle-stellate cells with vague fascicular pattern

Eosinophilic cytoplasm with long bipolar processes

Ovoid and elongated wavy nuclei with pinpoint nucleoli; occasional mitotic activity

Abundant collagenous matrix, including "keloid-like" collagen

Delicate thin-walled vasculature

Infiltrative; spindle-stellate cells with vague fascicular pattern

Eosinophilic cytoplasm with long tapering processes

Ovoid and wavy nuclei with pinpoint nucleoli; occasional mitotic activity

Abundant collagenous matrix with prominent small vessels

Spindle-stellate cells with vague fascicular pattern

Eosinophilic cytoplasm with long tapering processes

Ovoid and buckled nuclei with pinpoint nucleoli; inconspicuous mitotic activity

Abundant collagenous matrix with prominent small vessels

IHC: beta-catenin

Spindle-stellate cells with vague fascicular pattern

Eosinophilic cytoplasm with long tapering processes

Ovoid nuclei with pinpoint nucleoli; inconspicuous mitotic activity

Abundant "keloid-like' collagenous matrix with prominent small vessels

IHC: beta-catenin

DNA-seq:  CTNNB1 exon 3 mutation; c.121A>G (p.T41A)

Spindle-stellate cells with vague fascicular pattern

Eosinophilic cytoplasm with long tapering processes

Ovoid and wavy nuclei with pinpoint nucleoli; inconspicuous mitotic activity

Abundant collagenous matrix with prominent small vessels

IHC: beta-catenin

Infiltrative; spindle-stellate cells with vague fascicular pattern

Eosinophilic cytoplasm with long tapering processes

Ovoid and wavy nuclei with pinpoint nucleoli; occasional mitotic activity

Abundant collagenous matrix with prominent small vessels; entrapment of glandular epithelium