Fibrohistiocytic Tumor Research Articles

Fine-needle aspiration cytology of diffuse type tenosynovial giant cell tumor with malignant trasformation and review of literature.

Tenosynovial giant cell tumors (TGCTs) arise from the synovium of joint, bursa, and tendon sheath. Diffuse type often affects large joints, has higher recurrence rates, metastases, and malignant transformation potential compared to the localized type. The cytopathology of TGCT, a fibrohistiocytic neoplasm distinct from other giant cell-rich soft tissue tumors, is rarely reported. Here we describe cytomorphology of a case of TGCT that was initially diagnosed on fine-needle aspiration cytology (FNAC) consisting of a mixture of singly scattered polygonal or spindle mononuclear cells with hemosiderin laden macrophages, inflammatory cells, and a population of multinucleated osteoclast-like giant cells. Persistent symptoms and repeat excision were consistent with high-grade malignant transformation of the TGCT. Atypical cytologic features in a recurrent, infiltrative, or a metastatic lesion should raise suspicion for malignancy.

Plexiform fibrohistiocytic tumor: A series of 10 case studies.

We sought to investigate the clinicopathologic features and differential diagnosis of plexiform fibrohistiocytic tumor (PFHT) and its pathogenesis. Ten cases of PFHT were collected from Xi Jing Hospital, Fourth Military Medical University, from September 2008 to December 2022 for clinical data as well as microscopic and immunohistochemical observation. CCND1 gene amplification and break were assayed by fluorescence in situ hybridization (FISH). We report 10 cases of PFHT according to histologic classification. Seven cases were of histiocytoid type, and 3 had mucous degeneration in the nodules. One case was of fibroblastic type, which was mainly composed of fibroblast-like cells. Two cases were of mixed type. Immunohistochemically, the osteoclast-like multinucleated giant cells, histiocyte-like cells, and occasional spindle cells in the adjacent fascicles were reactive for CD68 (10/10), CD163 (5/8), CD10 (8/8), cyclin D1 (8/8), CDK4 (5/8), β-catenin (4/6), MITF (2/6), and PGP9.5 (4/5). Vimentin (9/9) was strongly positive in tumor cells and peripheral fibroblast-like cells. The positive index of Ki-67 was 5% to 40%, with an average of 20%. The FISH analysis showed neither amplification nor break of the CCND1 gene. All cases underwent surgical resection, and patients were followed up for 9 months to 11 years. Only 2 cases recurred. Plexiform fibrohistiocytic tumor is a low-grade malignant soft tissue neoplasm. The diagnosis mainly depends on histopathologic and immunohistochemical markers. Cyclin D1 and CD10 expression has diagnostic value for the diagnosis and differential diagnosis of PFHT combined with its plexiform morphology. The overexpression of cyclin D1 suggests an involvement of cell cycle regulatory genes in the pathogenesis of PFHT.

Analysis of surgical margins and prognostic factors in dermatofibrosarcoma protuberans after wide local excision: Amulticenter study of 116 Japanese patients.

Cutaneous dermatofibrosarcoma protuberans (DFSP) is a fibrohistiocytic tumor characterized by a high risk of local recurrence but a low risk of metastasis. Wide local excision (WLE) has been an important treatment option, but its clinical outcomes and safety have not been thoroughly evaluated in previous reports. The aim of this study was to determine appropriate surgical margins (deep and lateral) and prognostic factors associated with recurrence-free survival (RFS) of DFSP. A database collected by two dermatology departments in Japan was retrospectively reviewed to identify 116 patients with DFSP who underwent complete resection with WLE between 1994 and 2021. Sixty-one men (53%) and 55 women (47%) were included in our cohort. The primary sites of DFSP were as follows: 11 head and neck (9%); seven face (7%); 12 upper extremities (10%); 20 lower extremities (17%); and 66 trunk (57%). There were 103 cases (89%) of primary DFSP and 13 cases (11%) of recurrent DFSP. Total 10-year RFS was 96.6%. There were significant differences in RFS by tumor size (median size: 3 cm), disease status (primary versus recurrent DFSP), and fibrosarcomatous change (positive versus negative) (all p < 0.05). Two patients (1.7%) with buccal or head lesions had positive deep margins. In all cases, the lateral margin was negative at the postoperative evaluation. Tumor size, disease status, and fibrosarcomatous change are important risk factors for recurrence. Both face and head-neck lesions were more likely to have positive deep margins than other anatomic areas in DFSP. Although this study was limited by its retrospective design, a narrow 2-cm lateral margin is especially considered for low-risk patients.

Giant Cell Tumor of Soft Tissue Masquerading as a Fibroma - A Rare Clinical Entity

Giant cell tumor of the soft tissue (GCT-ST) is a rare and distinctive entity, separate from its bony counterpart, giant cell tumor of bone. This primary soft tissue tumor is often encountered in middle-aged individuals but rarely in children, with common sites including superficial soft tissue of the extremities. GCT-ST typically presents as a painless, slowly growing mass, emphasizing the importance of complete excision to prevent recurrences and metastasis. We present a case of GCT-ST in a 7-year-old boy with a nodular swelling on the right hip, initially suspected to be a fibroma. Histopathological examination revealed characteristic features of GCT-ST, including spindle and stellate cells, multinucleated giant cells, and haemosiderin-laden macrophages with metaplastic osseous tissue. This case adds to the limited literature on GCT-ST, highlighting its diverse clinical presentations and challenging diagnostic nature. The discussion includes a review of reported cases of GCT-ST, which have shown varied clinical presentations and outcomes. Histologically, GCT-ST resembles a giant cell tumor of bone, with positive staining for CD68, SMA, Vimentin, and p63. Imaging studies typically reveal a solid hemorrhagic mass. Differential diagnoses include benign and malignant soft tissue tumors rich in giant cells. Keywords: Giant Cell Tumor of Soft Tissue (GCT-ST), Rare, Fibro-Histiocytic Tumor Of Intermediate Malignancy, Soft Tissue Tumor, Rare Tumors In Children.

Morphological and immunohistochemical features can potentially help with the differential diagnosis of rare oral mesenchymal tumors

ObjectiveThe aim of this study was to evaluate the features of rare oral and maxillofacial benign and malignant tumors of fibroblastic, myofibroblastic and fibrohistiocytic origin in an attempt to contribute to the diagnosis of these tumors. MethodsThe sample consisted of 16 cases of benign fibrohistiocytic (BFH) tumor, myofibroma (MF), solitary fibrous tumor (SFT), fibrosarcoma (FS), dermatofibrosarcoma protuberans (DFSP), and myofibroblastic sarcoma (MFS), obtained from a laboratory of oral pathology. They were submitted to morphological, histochemical (Masson’s trichrome), and immunohistochemical (α-SMA, vimentin, desmin, CD34, Bcl-2, S100, CD68, CD99, and Ki-67) analysis. ResultsMorphological analysis revealed variable features in the tumors studied. Masson’s trichrome resulted in blue staining in most cases. Regarding the immunohistochemical features, all cases were positive for vimentin and negative for desmin. The BFH tumors exhibited positive staining for CD68 and S100, while MFs were positive for α-SMA and SFTs were positive for CD34, CD99 and Bcl-2. With respect to malignant tumors, DFSP was positive for CD34 and Bcl-2 and MFS was positive for α-SMA and Bcl-2, while FS was negative for most of the antibodies analyzed. A higher proliferation index (Ki-67) was observed in malignant tumors. ConclusionsConsidering their similarity, the use of auxiliary techniques might help in the differential diagnosis of these tumors.

Plexiform fibrohistiocytic tumor of elbow: A rare case report

Plexiform fibrohistiocytic tumor is a very rare tumor of soft tissue that affects usually adolescents and children. On histopathological examination it shows multiple small nodules or fascicles that are arranged in plexiform pattern, hence its name. Here we are presenting a case of occurrence of PFT in bilateral elbows. Patient presented with gradually increasing in size and painless swellings for 7 years. Excision was done and on the basis of histopathological and immunohistochemical examination diagnosis of PFT was reached.

Giant plexiform fibrohistiocytic tumor of the lower leg (a case report)

Giant plexiform fibrohistiocytic tumor of the lower leg (a case report)

Giant Cell Fibroblastoma of Hand in an Adult: An Uncommon Presentation

Giant cell fibroblastoma is a rare intermediate grade fibrohistiocytic tumour of childhood and even rarer in adults. It is seen in first decade of life. It is known for its recurrence, but its metastasis has never been reported. Giant cell fibroblastoma requires attention as it was previously misdiagnosed as sarcoma. So histology is mandatory and remains the gold standard for its diagnosis. We present a case of 21 year old female who presented with complains of painless lesion over the dorsal aspect of left hand.

Report of an Unusual Case of Hemosiderotic Fibrohistiocytic Lipomatous Tumor with Systematic Review of Clinicopathological Characteristics and Differential Diagnosis

The spectrum of lipomatous lesions ranges from benign to highly malignant disease. Differentiation between these mesenchymal lesions is important for pathologist as well as clinician to indicate prognosis and choose the most appropriate treatment. Hemosiderotic firohistiocytic lipomatous tumor (HFLT) is a rare subtype of lipomatous tumor. The diagnosis is usually based on clinical, histological, and immunohistochemical (IHC) information. We reported a case of 56 years old man with a painful mass in the dorsal aspect of the thigh showing an unusal clinical presentation but a characteristic histological and IHC features. In this article we have retrospectively reviewed the 67 cases of HFLT reported in literature so far along with one case reported at our institution. The review focuses on clinicopathological and histomorphological characteristics of HFLT and the related entities. The hallmark of HFLT and its related lesions is complex admixture of mature adipose tissue, spindle tumor cells with striking deposition of hemosiderin pigment. Even though HFLT shows marked predeliction for the distal extremeties especially the foot/ ankle with a female preponderance, they can occur at uncommon site such as thigh and also in males as seen in our case. Keywords: Pleomorphic hyalinizing angiectatic tumor, Hemosiderotic fibrolipomatous tumor, Myxoinflammatory Fibroblastic Sarcoma, Hemosiderin, Lipoma

Top 10 Differential Diagnoses for Desmoplastic Melanoma.

Desmoplastic melanoma is a rare subtype of melanoma mainly appearing on sun-exposed skin. Clinically, it is many times non-pigmented and therefore the diagnosis is often not suspected. Review article. In this paper we review the main histopathological, immunohistochemical, and molecular features of desmoplastic melanoma, as well as the top 10 morphologic differential diagnoses which should be considered in most cases. The histopathological pattern can be many times deceptive, mimicking a scar, a fibrous reaction, a fibrohistiocytic tumor such as a dermatofibroma, a vascular tumor such as angiosarcoma, a smooth muscle tumor such as leiomyosarcoma, or a neural tumor. Although an overlying atypical junctional melanocytic proliferation may be seen in most cases, it is absent in a significant percentage (up to 30%) of cases, making the diagnosis even more difficult in those instances. The range of diagnostic pitfalls is wide, which may present disastrous prognostic consequences. Desmoplastic melanoma is often a difficult diagnosis to make, as it frequently shows nonspecific clinical findings and overlapping histologic features with many other tumors. However, the potential clinical and prognostic consequences of misdiagnosis as another entity are great. Therefore, this diagnosis must always be kept in mind when encountering spindle cell tumors affecting the head and neck area.

Plexiform fibrohistiocytic tumor

Plexiform fibrohistiocytic tumors are rare, low-to-moderate malignant soft tissue tumors that occur primarily in children and adolescents and are located on the upper extremity. The diagnosis must be made histologically. We report on ayoung woman who presented agrowing, painless lesion on the cubital fossa. Histopathology as well as the standard of treatment are discussed.

Keloidal Dermatofibroma of the Face: A Rare Series of Three Cases

Dermatofibroma, also known as benign fibrous histiocytoma, is a cutaneous lesion that commonly affects young or middle-aged adults, with a slight preponderance in females. It usually presents as a single or multiple skin-coloured to reddish-brown nodule, primarily affecting the limbs. In the present case series, the authors reported three cases (two males and one female) of the keloidal variant of dermatofibroma, a benign fibrohistiocytic tumour. These cases involved patients aged between 32 and 55 years. All patients presented with nodular lesions on their faces, clinically diagnosed as dermatofibroma. Upon excision, the tumours exhibited circumscribed features with keloid-like areas, multinucleated giant cells, and inflammatory infiltrate. Keloidal dermatofibroma should be considered as a differential diagnosis when encountering tumours with keloid-like characteristics, especially in cases where incomplete excision may lead to recurrence. The present case series highlights the rarity of all three cases occurring on the face, as the prevalence of keloidal dermatofibroma is only 1% among other variants.

Diagnostic utility of CSF1 immunohistochemistry in tenosynovial giant cell tumor for differentiating from giant cell-rich tumors and tumor-like lesions of bone and soft tissue

BackgroundTenosynovial giant cell tumor (TSGCT) is a benign fibrohistiocytic tumor that affects the synovium of joints, bursa, and tendon sheaths and is categorized into localized TSGCT (LTSGCT) and diffuse TSGCT (DTSGCT). LTSGCT and DTSGCT are characterized by recurrent fusions involving the colony-stimulating factor 1 (CSF1) gene and its translocation partner collagen type VI alpha 3 chain. The fusion gene induces intratumoral overexpression of CSF1 mRNA and CSF1 protein. CSF1 expression is a characteristic finding of TSGCT and detection of CSF1 mRNA and CSF1 protein may be useful for the pathological diagnosis. Although there have been no effective anti-CSF1 antibodies to date, in situ hybridization (ISH) for CSF1 mRNA has been performed to detect CSF1 expression in TSGCT. We performed CSF1 immunohistochemistry (IHC) using anti-CSF1 antibody (clone 2D10) in cases of TSGCT, giant cell-rich tumor (GCRT), and GCRT-like lesion and verified its utility for the pathological diagnosis of TSGCT.MethodsWe performed CSF1 IHC in 110 cases including 44 LTSGCTs, 20 DTSGCTs, 1 malignant TSGCT (MTSGCT), 10 giant cell tumors of bone, 2 giant cell reparative granulomas, 3 aneurysmal bone cysts, 10 undifferentiated pleomorphic sarcomas, 10 leiomyosarcomas, and 10 myxofibrosarcomas. We performed fluorescence ISH (FISH) for CSF1 rearrangement to confirm CSF1 expression on IHC in TSGCTs. We considered the specimens to have CSF1 rearrangement if a split signal was observed in greater than 2% of the tumor cells.ResultsOverall, 50 of 65 TSGCT cases, including 35 of the 44 LTSGCTs and 15 of the 20 DTSGCTs, showed distinct scattered expression of CSF1 in the majority of mononuclear tumor cells. MTSGCT showed no CSF1 expression. Non-TSGCT cases were negative for CSF1. FISH revealed CSF1 rearrangement in 6 of 7 CSF1-positive cases on IHC. On the other hand, FISH detected no CSF1 rearrangement in all CSF1-negative cases on IHC. Thus, the results of IHC corresponded to those of FISH.ConclusionWe revealed characteristic CSF1 expression on IHC in cases of TSGCT, whereas the cases of non-TSGCT exhibited no CSF1 expression. CSF1 IHC may be useful for differentiating TSGCTs from histologically mimicking GCRTs and GCRT-like lesions.

Plexiform fibrohistiocytic tumor: a clinicopathological and immunohistochemical study of 39 tumors, with evidence for a CSF1-producing "null cell" population.

Plexiform fibrohistiocytic tumor (PFHT) is a mesenchymal tumor of intermediate malignancy, typically occurring in the superficial soft tissues of young patients and displaying a biphasic pattern, with nodules of histiocytoid cells surrounded by fascicles of myofibroblastic spindled cells. The pathogenesis of PHFT is unknown. We comprehensively studied 39 PFHT, occurring in 25 females (66%) and 13 males (34%), ranging from 2 to 55years of age (median 21years). The tumors most often occurred in the upper extremity (n = 16, 41%) and ranged from 0.4 to 6.1cm in size (median 1.5cm). One patient with known neurofibromatosis type 1 presented with metachronous tumors of the finger and back. Clinical follow-up (29 patients; range 5-168months; median 60months) showed 3 tumors to have recurred locally; none was metastasized. One patient died of an unrelated cause; all others were alive without disease at the time of last follow-up. Immunohistochemistry showed the histiocytoid nodules of all cases to contain CD163/CD11c-positive histiocytes and cells negative for both markers ("null cells"). CSF1 expression was present in "null cells" in 7/10 cases (RNAscope chromogenic in situ hybridization). The Ki-67 labeling index was very low (< 5%); Ki-67-positive cells within histiocytoid nodules appeared to represent "null cells." All tested cases were negative for significant mutations or fusion events (TruSight Mutation Panel, TruSight Fusion Panel, Mayo Clinic Melanoma Targeted Gene Panel). We conclude that PHFT may be even more indolent than has been appreciated, although classification as an "intermediate" tumor is correct. We hypothesize that the CSF1-producing "null cells" of PHFT may represent the neoplastic element, with the bulk of the tumor masses comprising recruited and reactive cell populations.

Clinical and histopathological analysis of 141 dermatofibrosarcoma protuberans in Korea: A comparative study according to trauma.

Dermatofibrosarcoma protuberans (DFSP) is a rare fibrohistiocytic tumour of unknown pathogenesis with intermediate malignant potential. Although trauma has been hypothesized as a predisposing factor for DFSP development, clinicopathological characteristics of trauma-related DFSP have not been investigated. This study investigated the differences between trauma-associated DFSP and trauma-unrelated DFSP. Patients histopathologically diagnosed with DFSP from January 2000 to December 2019 at the Dermatology Department were included. Clinical, histopathological, prognostic features and trauma history were analysed. We recruited 141 patients with DFSP (mean age, 36.1 years; male: female, 1:1.01). Recurrence and systemic metastasis were observed in 15.6% and 2.8% of patients, respectively. Older patients were likely to develop DFSP at the trauma sites more frequently on the face and lower legs. The active-growing lesions were more frequently associated with trauma-related DFSP. Multivariable logistic regression revealed that age at diagnosis (OR: 1.031; 95% CI: 1.004-1.059; p=0.024) and tumour growth (OR: 3.336; 95% CI: 1.162-9.578, p=0.025) were significantly associated with trauma-related DFSPs. The age at diagnosis, lesion location and tumour growth were associated with DFSPs in this study. Analysis of DFSP with trauma history provides a deeper understanding of long-term trauma effects on sarcoma development.

The Uncancerous Helix-Benign Fibrous Histiocytoma

Benign fibrous histiocytoma occurs as an exceptional, painless, subcutaneous, mesenchymal, fibrohistiocytic neoplasm devoid of dermal incrimination. Additionally designated as deep dermatofibroma, deep seated benign fibrous histiocytoma commonly emerges within subcutaneous tissue, deep seated soft tissue or parenchymal organs. Generally, benign fibrous histiocytoma arises in adult males &gt; 25 years and appears between 6 years to 84 years with a median age of disease emergence at 40 years. A male predominance is observed. Commonly, benign fibrous histiocytoma emerges within lower or upper extremities, head and neck or trunk. Neoplasms confined to deep soft tissue of retroperitoneum, mediastinum or pelvis are infrequently discerned [1,2]. Deep seated benign fibrous histiocytoma emerges as a painless, gradually progressive, well circumscribed or encapsulated tumefaction [1,2]. Grossly, firm, yellow to tan, well circumscribed tumefaction encompassed with a pseudo-capsule is discerned. Pseudo-capsule may be absent where tumefaction extends to the cutis [1,2]. Characteristically, tumour magnitude is ~ 4 centimetres and varies from 0.5 centimetres to 25 centimetres. Cut surface exhibits variable foci of haemorrhage [1,2]. Upon microscopy, neoplasm exhibits a prominent storiform pattern configured of uniform, spindle-shaped cells imbued with eosinophilic cytoplasm with ill defined cellular perimeter and bland, elongated or plump nuclei with vesicular chromatin and delicate nucleoli. Tumour nuclei are devoid of nuclear atypia [1,2]. tumefaction is admixed with disseminated lymphocytes, plasma cells multinucleated giant cells, osteoclastic giant cells or foamy macrophages [1,2]. Frequently, prominent vascular articulations may configure a hemangiopericytoma-like pattern. Mitotic figures appear ≤5 mitosis per 10 high power fields [1,2]. Intervening stroma is myxoid or hyaline. Focal necrosis or tumour infiltration of lymphatic and vascular configurations is exceptional. Tumour perimeter is non-infiltrative and peripheral entrapment of adipose tissue is absent. Focal entrapment of collagen fibres may occur [1,2].

33979 Minimum resection margins for fibrohistiocytic tumors: A systematic review to inform a probability model

Background: Atypical fibroxanthomas (AFX) and cutaneous undifferentiated pleomorphic sarcomas (cUPS) are fibrohistiocytic tumors with significant clinical and histologic overlap. The metastatic potential of both pathologies necessitates treatment with either wide local excision (WLE) or Mohs micrographic surgery (MMS) to attain margin clearance. Few studies have investigated the optimal resection margins in WLE or the first stage of MMS when treating AFX or cUPS, and currently no recommendations exist.

35224 Identifying a correlation between preceding trauma and development of dermatofibrosarcoma protuberans: A review of the literature

Background: Dermatofibrosarcoma protuberans (DFSP) is a malignant fibrohistiocytic neoplasm that is slow-growing, has low metastatic potential, and is locally infiltrative with a predisposition for recurrence. The development of DFSP can occur spontaneously, but anecdotal evidence suggests a correlation between preceding injury and tumor onset.

MORPHOLOGICAL AND IMMUNOHISTOCHEMICAL FINDINGS OF UNUSUAL ORAL MESENCHYMAL TUMORS

<h3>Objectives</h3> To evaluate the features of uncommon oral benign and malignant tumors of fibroblastic, myofibroblastic, and fibrohistiocytic origin to better understand the diagnostic challenges of these tumors. <h3>Study Design</h3> This study evaluated benign fibrohistiocytic tumor (BFH; <i>n</i> = 4), myofibroma (MF; <i>n</i> = 2), solitary fibrous tumor (SFT; <i>n</i> = 6), fibrosarcoma (FS; <i>n</i> = 2), dermatofibrosarcoma protuberans (DFSP; <i>n</i> = 1), and myofibroblastic sarcoma (MFS; <i>n</i> = 1) obtained from a diagnostic service. We carried out morphologic and immunohistochemical (αSMA, vimentin, desmin, CD34, Bcl2, S100, CD68, CD99) analyses. <h3>Results</h3> Morphologic analysis showed several features in tumor cells and stroma of the tumors (multinucleated cells, clear cells, hypercellular and hypocellular areas). Immunohistochemistry demonstrated that all cases were positive for vimentin and negative for desmin. BFH tumors exhibited immunopositivity for CD68 and S100, whereas MFs were positive for αSMA and SFTs for CD34, CD99, and Bcl2. Regarding malignant tumors, DFSP was positive for CD34 and Bcl2, and MFS was positive for αSMA and Bcl2, whereas FS was negative for most of the antibodies analyzed. Furthermore, malignant tumors exhibit a higher proliferation index (Ki-67 > 10%). <h3>Conclusions</h3> Considering their morphologic similarity, the use of immunohistochemistry is of great value to help in the differential diagnosis of these tumors.

Tarsal Fibroma of the Eyelid

An 83-year-old man presented with a painless, firm, right upper eyelid lesion, present for 4 years. Eyelid eversion revealed a firm pedunculated lesion, approximately 1 × 1-cm diameter, with flattened top molded to the globe contour and overlying conjunctival follicular reaction (Fig A). The lesion was excised at the base and found to macroscopically originate from the tarsus. Histopathology showed spindle cells in a dense collagen matrix (Fig B). Immunohistochemical staining of the spindle cells was diffusely positive for CD34 (Fig C) and focally positive for Factor XIIIa (Fig D), markers for fibrohistiocytic tumors.