(1,3,12,20) In a study of 115 DLs, Henricks et al (12) described low-grade tumors resembling desmoid-type fibromatosis as well as a tumor with myofibroblastic cells admixed with amianthoid fibers reminiscent of a myofibroblastoma
. Subsequently, in a review of 32 DLs, Hasegawa et al (20) reported 3 tumors with myofibroblastic features, including one that resembled inflammatory fibrosarcoma.
Benign tumors were reported as glomus tumor, epidermal cyst, giant-cell tumors of the tendon sheath, pyogenic granuloma, neurinoma, schwannoma, lipoma, cystic hygroma, hemangioma, arteriovenous malformation, fibroma, fibrolipoma, ganglion cyst, infantile digital myofibroblastoma
, dermatofibroma, and verruca vulgaris; whereas the malignant tumors were identified as squamous cell carcinoma (SCC), basal cell carcinoma (BCC), malignant melanoma, fibrohistiocytic malignant tumor, and synovial sarcoma.
Other differential diagnoses include cellular angiofibroma and vulvovaginal myofibroblastoma
. Cellular angiofibromas are uniformly cellular with thick-walled, hyalinised blood vessels without surrounding aggregation of epithelioid or plasmacytoid cells.
are devoid of mammary epithelium and contain thickbundles of hyalinized collagen between the spindle cells.
Diagnostic problems can occur when it is not considered as a change that terms the entire lesion and overlooked in core biopsies performed for diagnosis of mass lesions or when it is confused with neoplasias, such as low-grade angiosarcoma and myofibroblastoma
. Therefore, we suggest that PASH should be kept in mind in the diagnosis of mass lesions.
PASH has to be differenciated from a low-grade angiosarcoma, benign myofibroblastoma
and mammary hamartoma.
of soft tissue: A tumour closely related to spindle cell lipoma.
Mammary type myofibroblastoma
shows (long) fascicles, short stubby nuclei, broad bands collagen, as well as CD34 +/-, desmin +, SMA -/+ and RB1 deletion.12
The overall histopathological and immunostaining patterns were interpreted as a myofibroblastoma
with prominent adipocytic component.
Intranodal palisaded myofibroblastoma
(IPM), also known as "intranodal hemorrhagic spindle cell tumor with amianthoid fibers," is a benign mesenchymal tumor of the lymph node originating from smooth muscle cells and myofibroblasts often with the presence of amianthoid fibers [1, 2].
"Cellular angiofibroma: analysis of 25 cases emphasizing its relationship to spindle cell lipoma and mammary-type myofibroblastoma
," Modern Pathology (2011) 24, 82-89.
As PASH may occasionally adopt a solid fascicular growth pattern, it can be confused with pure mesenchymal spindle cell lesions (myofibroblastoma
; leiomyoma; and fibromatosis) or fibroepithelial lesions (fibroadenoma; hamartoma; and phyllodes tumors) containing a spindle cell component [11,12].