Benign fibrous histiocytoma dog removal cost histiocytoma of the nasal vestibule report of a case and review of literature

Benign benign fibrous histiocytoma (BFH) was first described as a separate clinical entity in the histiocytoma dog removal cost 1960s after a lengthy process aiming towards a precise identification histiocytoma dog removal cost of fibrohistiocytic lesions and the distinction between benign and malignant histiocytoma dog removal cost variants [ 1]. It is now considered a benign mesenchymal lesion composed of histiocytoma dog removal cost fibroblasts and histiocytes arising in the cutaneous and non-cutaneous soft tissues, although disputes still exist on whether this is a true histiocytoma dog removal cost tumor or a reactive mass at least as for the histiocytoma dog removal cost cutaneous form [ 2, 3]. Confusion on the nature of fibrohistiocytic lesions also accounts for histiocytoma dog removal cost the variety of names used to describe this tumor and histiocytoma dog removal cost its variants: dermatofibroma, sclerosing hemangioma, adult xanthogranuloma, fibroxanthoma, and nodular subepidermal fibrosis are some of the terms more histiocytoma dog removal cost commonly used in the past to identify this tumors [ 1].

While cutaneous BFH (dermatofibroma) usually originates in sun-exposed skin, non-cutaneous soft tissue BFH usually presents itself in subcutaneous tissues histiocytoma dog removal cost of the extremities and more rarely in visceral spaces like histiocytoma dog removal cost the retroperitoneum and pelvis; localizations in tendons are rare and visceral presentations anecdotal [ 3]. The “deep” soft tissue variant of the tumor seems to be relatively histiocytoma dog removal cost more frequent in young children, especially in the head and neck region [ 4]. BFH arising in the orbital tissues represents the most frequent histiocytoma dog removal cost primary mesenchymal tumor of the orbit in adult patients and histiocytoma dog removal cost accounts for most of the head and neck localizations that histiocytoma dog removal cost would otherwise be rare [ 5]. In the ENT practice BFH has been more commonly encountered histiocytoma dog removal cost in the bone and soft tissues of the oral cavity histiocytoma dog removal cost such as in the tongue, gingival or alveolar ridge, mandible, maxilla, lips, soft palate, and floor of the mouth. The nasal cavity and paranasal sinuses, larynx, trachea, temporomandibular joint, and submandibular and parotid glands are more rarely involved [ 5]. A malignant subtype of fibrous histiocytoma has also been described histiocytoma dog removal cost [ 2, 3]. Tumors of the nasal vestibule are generally rare and reports histiocytoma dog removal cost of nonepithelial variants absolutely exceptional [ 6] ; no definite cases of fibrohistiocytic tumors in this site are histiocytoma dog removal cost present in literature so far.

Dermatofibromas (cutaneous fibrous histiocytomas) usually present as rapidly evolving, yet asymptomatic single, round, oval to targetoid well circumscribed hard papules (more rarely plaques or tumors) and mainly occur on the extremities and trunk; rarely such lesions have been reported on the face. They are quite common (compared to noncutaneous variants) and may develop at any age, but particularly during the third and fourth decades. Multiple tumors are regarded as a marker of immune suppression histiocytoma dog removal cost or autoimmune disease (sjögren syndrome, pemphigus vulgaris, myasthenia gravis, ulcerative colitis treated with immunosuppressive drugs, transplant recipients or AIDS patients). The etiology has not been established unequivocally. It remains controversial whether it is an inflammatory or neoplastic histiocytoma dog removal cost process [ 2].

On histological examination dermatofibromas present as ill-defined, predominantly dermal lesions characterized by a variable number of spindle histiocytoma dog removal cost and/or rounded cells. They show a dense infiltrate of spindle-shaped and/or round cells, some of which may be fibrocytes and/or macrophages, centered in the reticular dermis and sometimes, the upper part of the subcutis. Early lesions are rich in macrophages. Lymphocytes often spread throughout the lesion with frequent prominence in histiocytoma dog removal cost the peripheral part, but may be absent in advanced stages. At times foam cells may be prominent in deeper areas histiocytoma dog removal cost adjacent to subcutaneous fat. Dermatofibromas reveal a variable immunohistochemical profile: early lesions are rich in reactivity for macrophage markers such histiocytoma dog removal cost as PGM1 or KP1 (CD68), but also exhibit strong reactivity for factor xiiia in both histiocytoma dog removal cost macrophages and fibroblasts. This reactivity is mostly seen at the periphery and continuously histiocytoma dog removal cost diminishes with the ageing of the lesion to be completely histiocytoma dog removal cost absent in atrophic variants [ 2].

Benign fibrous histiocytoma of bone is a benign lesion composed histiocytoma dog removal cost of spindle-shaped fibroblasts, arranged in a storiform pattern, with a variable admixture of small, multinucleated osteoclast-like giant cells. Foamy cells (xanthoma), chronic inflammatory cells, stromal hemorrhages and hemosiderin pigment are also frequently encountered. It most frequently occurs in the long bones (40% of cases) mainly involving the femur and tibia and pelvic bones (25%), in particular the ilium. However, this tumor may involve virtually any bone including the facial histiocytoma dog removal cost skeleton and skull. In the long bones, benign fibrous histiocytoma is chiefly located in the epiphysis or histiocytoma dog removal cost diaphysis [ 3].

No definite cases involving the nasal vestibule have been identified, so far. One case of a not-better-specified histiocytoma of the nasal vestibule has been reported in histiocytoma dog removal cost 1964 [ 24]. Despite our efforts it was impossible to access the original histiocytoma dog removal cost document through our institution’s library and allied services. Anyhow, given the amount of time that has passed, there would have been no possibility to re-assess the case using modern criteria. In fact, knowledge over histiocytic lesions at that time was limited, in the absence of a clear-cut definition of this type of neoplasms and an univocally histiocytoma dog removal cost accepted classification of soft tissue tumors in general; thus, even in the presence of a perfectly performed direct microscopic histiocytoma dog removal cost assessment with the instruments available then, an accurate differential diagnosis between BFH and other soft tissue histiocytoma dog removal cost neoplasms should have been extremely difficult especially if one considers histiocytoma dog removal cost the fact that immunohistochemical marking was not available yet. Case 2 presented in the work by perzin et al. In 1980 [ 12] refers to a tumor approaching the region of the nasal histiocytoma dog removal cost vestibule but the description and the fact the it was histiocytoma dog removal cost excised through polipectomy indicate that the mass had a tendency histiocytoma dog removal cost to grow towards the interior of the nasal cavity.

In the area of the nose and paranasal sinuses patients histiocytoma dog removal cost with soft tissue BFH usually present no history of pain histiocytoma dog removal cost and the predominant clinical feature of discomfort and/or nasal obstruction from a rapidly enlarging mass. Swelling in the affected area, nasal discharge, epistaxis and loosening of teeth, facial asymmetry and proptosis may be present in some cases. In the presence of CT imaging showing aggressive bone destruction histiocytoma dog removal cost it may be difficult to differentiate these lesions from some histiocytoma dog removal cost malignant lesions located in the sinonasal cavity such as squamous histiocytoma dog removal cost cell carcinoma. The diagnosis of FH is based mainly on histological findings histiocytoma dog removal cost [ 16]. In the presence of involvement of the more internal part histiocytoma dog removal cost of the nasal cavities and the paranasal sinuses, superimposed sinonasal pathology such as rhinosinusitis with dense secretions and histiocytoma dog removal cost mucocele may originally mask the underlying condition [ 17, 20].

Contrary to the cutaneous form, deep lesions tend to be well-circumscribed and pseudo-encapsulated with occasional areas of hemorrhage. Deep fibrous histiocytomas usually show a prominent storiform pattern, sometimes combined with hemangiopericytomalike areas. Contrary to conventional cutaneous lesions, most lesions present a certain monomorphism and usually lack secondary histiocytoma dog removal cost elements such as foamy cells and giant cells but usually histiocytoma dog removal cost show scattered lymphocytes. The tumor cells are cytologically bland and generally spindle-shaped with elongated or plump vesicular nuclei and eosinophilic, ill-defined cytoplasm. These lesions usually lack pleomorphism or hyperchromasia, and mitoses, although occasionally present, are usually less than 5 per 10 high power fields histiocytoma dog removal cost [ 3]. In BFH, immunohistochemistry is positive for CD68, 1-antitrypsin, 1-antichymotrypsin, and vimentin, whereas it is negative for cytokeratin, epithelial membrane antigen, smooth muscle actin, S-100 protein, and CD34 [ 25]. Solitary fibrous tumor differs from BFH as it is highly histiocytoma dog removal cost positive for CD34. Differentiation between BFH and neurofibroma (NF) can be based on NF positivity for S-100, and the presence of more frequent mitoses and different fascicle histiocytoma dog removal cost configuration in neurofibromas. The negativity for SMA and S-100 helps differentiation from leiomyosarcoma and neurogenic tumors [ 5].

Little is known on the possible genetic background leading to histiocytoma dog removal cost the formation of BFH most probably due to the rarity histiocytoma dog removal cost of the tumor and the minor importance it is granted histiocytoma dog removal cost when compared to malignant variants. There has been a single report of a t(16;17)(p13.3;q21.3) translocation in a deep BPH of the thigh [ 26]. Interestingly a large part of the cases of noncutaneous BPH histiocytoma dog removal cost reported in literature originate from the area of far east; it is not clear whether this association is due to histiocytoma dog removal cost a major attention to the topic by the local medical histiocytoma dog removal cost communities or a truly higher incidence of the pathology in histiocytoma dog removal cost this region and whether a presumed higher occurrence rate is histiocytoma dog removal cost to be attributed to genetics, ambient factors or both.

The malignant variant of fibrohistiocytic tumors is considered as a histiocytoma dog removal cost highly aggressive sarcoma and is usually distinguishable from benign variants histiocytoma dog removal cost not only by its aggressive clinical course but also by histiocytoma dog removal cost the high mitotic rate cellular pleomorphism and atypical cells and histiocytoma dog removal cost by the tendency versus surrounding tissue invasion [ 27, 28]. In some cases however differential diagnosis might be challenging [ 29]. Not without extensive questioning on the exact histopathological and clinical histiocytoma dog removal cost profiles of the cases by the reporting authors, there have been reports of malignant fibrous histiocytoma arising in histiocytoma dog removal cost the same site or close proximity of a previously excised histiocytoma dog removal cost lesion defined as BFH [ 28, 29].

Given the good visibility of the lesion, in our opinion, localizations in the most external part of the nasal cavities histiocytoma dog removal cost such as the case presented, do not require the same radiological work up (CT and eventual RM) as those located deeper in the nose, unless bone involvement is presumed or other elements of suspicion histiocytoma dog removal cost are present in a thorough endoscopic examination.

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