Plexiform Fibrohistiocytic Tumor: Ultrastructural Studies May Aid in Discrimination from Cellular Neurothekeoma
Department of Pathology, The Children's Hospital, Aurora, Colorado 80045, USA.Ultrastructural Pathology (Impact Factor: 1.08). 12/2009; 33(6):286-92. DOI: 10.3109/01913120903348860
Plexiform fibrohistiocytic tumor is a low-grade soft tissue malignancy that can at times be difficult to differentiate from the less biologically aggressive cellular neurothekeoma. The two entities, which may display identical clinical and histological features, cannot be distinguished by immunohistochemical or molecular diagnostic means. Electron microscopy may enable the accurate identification of problematic examples and thus aid in resolving these occasionally occurring diagnostic dilemmas. To illustrate typical variations in the ultrastructural appearance of plexiform fibrohistiocytic tumor, the authors present two diagnostically noncontroversial examples, and to demonstrate the potential diagnostic utility of electron microscopy in this setting, they present an example of plexiform fibrohistiocytic tumor that could not otherwise have been distinguished from cellular neurothekeoma.
- European journal of dermatology: EJD 07/2010; 20(4):541-2. DOI:10.1684/ejd.2010.1005 · 1.99 Impact Factor
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ABSTRACT: Plexiform fibrohistiocytic tumor (PFH) and cellular neurothekeoma (CN) are dermal neoplasms that present many histological and immunophenotype similarities as well as unknown histogenesis. Recently, the ultrastructural detection of zebra body-like inclusions in lesional histiocytes has been considered crucial to favor the diagnosis of PFH over that of CN. Here we report two examples of dermal tumors that were diagnosed as CN. Electron microscopy revealed cytoplasmic collections of myelin and zebra body-like inclusions in tumor cells; these inclusions focally merged together or with multivesicular bodies; tumor cells also showed collagen secretion granules and fibripositors, i.e., channels containing single, double or multiple copies of collagen fibrils. These observations support the view that PFH and CN have a common histogenesis and consists of cells sharing phagocityc and fibrillogenic abilities.Ultrastructural Pathology 12/2010; 34(6):366-70. DOI:10.3109/01913123.2010.513079 · 1.08 Impact Factor
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ABSTRACT: Plexiform fibrohistiocytic tumor is an extremely rare soft tissue tumor with a low malignancy potential. The patient is usually a child or a young adolescent and the tumor is usually localized in the upper extremities. We report on a case of a 21-year old male with a plexiform fibrohistiocytic tumor in the left fibula admitted to our hospital due to a swelling and pain in the left lower extremity. Radiologically a lytic lesion in the distal end of left fibula consistent with a non-aggressive lesion with low biological activity was found. Treated with curettage, the specimen revealed plexiform proliferation of mononuclear histiocyte-like cells, multinucleated osteoclast-like cells, and spindle fibroblast-like cells in variable proportions histopathologically. Immunohistochemical stains were positive for CD68 in scattered fashion in histiocytes and giant cells, and spindle like cells showed positivity for smooth muscle actin. Under electron microscopy, rough endoplasmic reticulum and collagen bundles in the spindle cells suggested fibroblastic differentiation. Also multiple large electron-dense lysosomal granules in histiocytoid cells were found. Multinucleated giant cells exhibited osteoclast-like appearance. All these findings suggested plexiform fibrohistiocytic tumor. Interestingly, the tumor was localized in bone. During the follow up for 27 months after the resection, there was no recurrence or metastasis.Pathology International 11/2013; 63(11):554-8. DOI:10.1111/pin.12100 · 1.69 Impact Factor
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