Palisaded myofibroblastoma simulating chronic primary lymphadenopathic Kaposi's sarcoma

Intranodal palisaded myofibroblastoma; a case report and review of the literature

Intranodal palisaded myofibroblastoma (IPM) also called as intranodal hemorrhagic spindle cell tumor with amianthoid fibers is a distinctive and rare mesenchymal neoplasm of lymph nodes. This entity generally misdiagnosed as intranodal Kaposi's sarcoma or schwannoma in past. In contrast to Kaposi's sarcoma, it behaves in a benign fashion and does not need any further therapy except total surgical resection of the mass. This neoplasm has a great predilection for the inguinal region. The lesion presents typically as a unilateral, painless, solitary mass. To our knowledge, approximately 53 cases of IPM have been reported in the English-language literature. We present a 43-year-old-male patient with IPM and discuss histological, immunohistochemical features and pathogenesis of this rare benign neoplasm.

Recurrent intranodal palisaded myofibroblastoma with metaplastic bone formation

Intranodal palisaded myofibroblastoma (IPM) is a rare primary nonlymphoid tumor of the lymph node, which can easily be mistaken for other spindle cell tumors. Intranodal palisaded myofibroblastoma is thought to arise from intranodal myofibroblasts, a finding that is supported by its immunophenotype, positive immunostaining for actin and vimentin, and negative immunostaining for desmin. Characterized by a benign clinical course, IPM is treated by simple surgical excision. We describe a 49-year-woman, who had cadaveric renal transplantation in 1992 and recurrent IPM 41/2 years after its original excision. To our knowledge, this case represents only the second known case of recurrent IPM. The histologic feature of metaplastic bone formation in this case has not been previously described in IPM.

Aspiration biopsy cytology of intranodal myofibroblastoma: case report with immunocytochemical analysis

Intranodal myofibroblastoma (IM) is a recently delineated clinicopathologic entity represented by a myofibroblastic proliferation of the lymph node. It usually occurs at the groin and presents clinically as a single enlarged lymph node. Its clinical behavior is entirely benign and local excision is curative. The authors herein report a case of IM diagnosed by aspiration biopsy cytology (ABC). The main diagnostic clues to the cytologic diagnosis of this entity as well as the differential diagnosis are presented.

Myofibroblastoma of the axilla

A mass in the axilla of a 47-year-old woman was biopsied and resected. The mass was composed of a loosely distributed population of spindle cells that were immunoreactive for smooth-muscle actin. Ultrastructurally, the cells possessed abundant endoplasmic reticulum, and some contained peripheral smooth muscle myofilaments, establishing that they were myofibroblasts. Mitotic activity was sparse, there was no cytologic atypia, and by flow cytometry the tumor was diploid with a low S phase. A diagnosis of myofibroblastoma was favored, although the possibility of a low-grade sarcoma could not be excluded. There has not been any indication of recurrence over a 4-month period of follow-up.

Collagen composition and ultrastructure of the so-called amianthoid fibres in palisaded myofibroblastoma. Ultrastructural and immunohistochemical study

A very prominent feature of the recently described intranodal palisaded myofibroblastoma is the occurrence of stellate crystalline extracellular deposits known as 'amianthoid fibres', and thought to represent abnormally thick collagen fibrils. We showed at the ultrastructural level that these deposits are composed of fibrils with the periodicity and width typical of normal native collagen. Using antibodies directed against various extracellular components, we have determined that these structures contain type I and III collagens. Our results indicate that the crystalloid deposits in intranodal palisaded myofibroblastoma called 'amianthoid fibres' do not contain giant collagen fibrils widely regarded as characteristic of the morphological concept 'amianthoid' in other locations.