patternless pattern

patternless pattern

A term coined by Arthur Purdy Stout for the appearance by low-power microscopy of fibrous mesothelioma, which has a vague storiform pattern. The term has also been applied to hemangiopericytoma and solitary fibrous tumours.
References in periodicals archive ?
The patternless pattern consists of fibroblast-like cells and connective tissue arranged in a random or disorderly pattern.
In contrast to ESTP, solitary fibrous tumor is composed of bland ovoid-shaped to spindle-shaped cells without the cytologic features of perineurioma, arranged in the so-called patternless pattern, and has blood vessels often showing a hemangiopericytoma-like branching.
14] Morphologically, SFTs are well-circumscribed but not encapsulated tumors composed of bland spindle-shaped cells with several architectural appearances, including a storiform pattern, fascicles of spindle cells with a wavy, neural appearance, a patternless pattern, abundant myxoid matrix in areas, densely cellular fascicles of spindle cells with a herringbone pattern, and SFTs with atypical multinucleated giant cells admixed with the spindle cell proliferation.
Microscopically, most of the tumors are composed of spindle cells, which are arranged in interlacing fascicles or have a short storiform arrangement, so-called patternless pattern.