Atypical fibrous histiocytoma of the skin and subcutis in childhood and adolescence

The authors have observed 15 examples of a distinctive fibrohistiocytic lesion in children and adolescents which they chose to designate as "atypical fibrous histiocytoma" (AFH). Patient ages ranged from 1 to 19 years (mean 9.3 yr.). Only two cases were encountered in the first year of life, but 7 were seen in children under the age of 10 yr. The anatomic distribution of AFH showed a tendency for a truncal origin (66%), and none was located in the skin of the face, neck, or scalp. Tumor sizes ranged from 1 to 3 cm, and one-third were 2 cm or greater in maximum dimension. Histologically, AFH was characterized by a multinodular, dermal or dermal-subcuticular proliferation of spindle cells, with tapered, cytologically bland nuclei. However, nucleocytoplasmic ratios were increased when compared with those of normal fibroblasts. Nuclear chromatin was dispersed or vesicular; nucleoli were seen in a minority of cases, but mitotic activity was regularly present. Admixed giant cells were present but infrequent, cellularity was dense, and a storiform growth pattern was consistently seen. Mean followup in this group of cases averaged 75 mo. Seven patients (47%) had tumor recurrences after initial excision; in two of these, tissue margins had been free of involvement. The authors conclude that AFH of childhood is analogous to a lesion that has previously been reported as "benign fibrous histiocytoma" in adults. Complete excision and regular postoperative surveillance are recommended for these tumors.     

Aneurysmal fibrous histiocytoma showing transition from factor XIIIa-positive to -negative

A 39-year-old woman visited us because of a subcutaneous induration on her forehead of 7 months' duration. The tumor was tender, firm, and colored blue-black. Microscopically, the tumor was composed of fibroblastic and histiocytic cells showing no atypicality. In some part intra- or extracellular haemosiderin was diffusely seen. There were some blood-filled spaces of varying size without endothelial lining. From these findings, this case was diagnosed as aneurysmal fibrous histiocytoma (AFH), a variant form of dermatofibroma. Immunohistochemical analysis showed that factor XIIIa-positive histiocytic cells were distributed in the area without haemosiderin, but such cells were absent in the area with its deposition. Furthermore, the cells near the blood-filled space showed transition from factor XIIIa-positive to -negative, suggesting that the stromal instability induced by the attenuation of factor XIII may lead the formation of the blood-filled spaces in AFH.     

Pleomorphic angiomatoid fibrous histiocytoma: a case confirmed by fluorescence in situ hybridization analysis for EWSR1 rearrangement

Angiomatoid fibrous histiocytoma (AFH) is a neoplasm of uncertain histogenesis with intermediate malignant potential. It occurs in superficial soft tissues in any age group and at any body site, although the typical example occurs on extremities in children/young adults. The neoplasm is usually composed of a bland histiocytoid proliferation of cells with eosinophilic cytoplasm forming a syncytium, often surrounded by a dense fibrous pseudocapsule and lymphoid infiltrate, with abundant intralesional hemorrhage forming blood-filled spaces. AFH may show striking pleomorphism and mitotic activity, and such cases can lead to confusion with other atypical mesenchymal lesions, including pleomorphic sarcomas. Recent findings have shown that a majority of cases of AFH have translocations involving the EWSR1 or FUS genes. We present a diagnostically challenging case of AFH with pleomorphic features and minimal lymphoid and angiomatoid changes involving the superficial subcutis and deep dermis on the scalp of an 8-year-old boy. "Areas with typical AFH morphology were identified and the diagnosis confirmed with identification of an EWSR1…" rearrangement detected by fluorescence in situ hybridization. Pleomorphic AFH should be included in the differential diagnosis of atypical mesenchymal tumors of skin and superficial subcutis and molecular testing may prove helpful in this regard.     

Atypical cutaneous fibrous histiocytoma

We report seven cases of atypical cutaneous fibrous histiocytoma, which appears to be a variant of cutaneous fibrous histiocytoma (dermatofibroma). These patients are all middle-aged women (mean, 39 years old) with small nodules occurring on the trunk and limbs. The lesions are characterized by marked focal cellular atypia, the absence of mitoses, and xanthomatous changes in both mononuclear and giant cells--all found within a small dermal nodule (approximately 1 cm) separated from an acanthotic epidermis by a Grenz zone. Their benign nature is demonstrated by the absence of recurrence, even after 9 years follow-up time.     

Malignant fibrous histiocytoma of the scalp. Multidisciplinary treatment

BACKGROUND: Malignant fibrous histiocytomas (MFH) are uncommon in the skin, and even less frequent on the scalp. On the scalp they are often very difficult to excise and it is even more difficult to close the resulting wound. OBJECTIVE: To review all malignant fibrous histiocytomas diagnosed and treated in our Department during the past 6 years, and to describe the multidisciplinary procedure employed to treat one special case of aggressive malignant fibrous histiocytoma on the scalp that recurred twice. RESULT: Malignant fibrous histiocytomas represent 0.01% of malignant cutaneous tumors in our area. The immediate results after a multidisciplinary treatment performed on a recurrent malignant fibrous histiocytoma located on the scalp were excellent, but recurrence was observed 6 months later. Two years later we have also treated another case of MFH on the scalp. The same surgical technique was performed, but the patient received high-dose-methotrexate-based neoadjuvant chemotherapy (HD-MTX). One year later, this patient is still alive and no signs of recurrence have been detected. CONCLUSION: When malignant fibrous histiocytoma occurs on the scalp it must be treated immediately by means of an excision with a large peripheral edge of 2 cm from the visual or CAT limits of the lesion, since the first treatment must be definitive.     

Metastatic aneurysmal fibrous histiocytoma in a 20-year-old woman: A rare case report with review of the literature and discussion of its genomic features

Aneurysmal fibrous histiocytoma is an uncommon variant of cutaneous fibrous histiocytomas with a local recurrence rate of 19%. We present a case of aneurysmal fibrous histiocytoma in a 20-year-old female with a regional lymph node metastasis and subsequent satellite nodule. The patient initially presented with a 1-month history of two palpable nodules in left lower anterior shoulder and left axilla. Needle core biopsies from both lesions revealed an atypical spindle cell neoplasm with a differential diagnosis of aneurysmal fibrous histiocytoma and angiomatoid fibrous histiocytoma. The axillary dissection confirmed a metastatic deposit in 1 out of 22 lymph nodes. At 6 months a satellite nodule arose between the resection scar and the axilla histopathologically demonstrating a cellular spindle cell nodule at the dermis subcutaneous junction with large, blood-filled pseudovascular spaces lined by histiocytes. The periphery of the lesion showed collagen trapping without a lymphoplasmacytic infiltrate. The lesional cells were diffusely positive for CD10 and focally for CD68 and Illumina RNA fusion panel sequencing was negative. Herein we present this case of metastatic aneurysmal fibrous histiocytoma with review of the literature and discussion of biology, cytogenetic alterations, and differential diagnosis.     

Malignant fibrous histiocytoma

A 74-year-old man presented with a malignant fibrous histiocytoma (MFH) on the lower leg. Wide local excision was performed and no recurrence has occurred to date. The pathological features which distinguish MFH from other sarcomas are now well denned and deserve wider recognition.     

Atypical fibrous histiocytoma of the skin with CD30 and p80/ALK1 positivity and ALK gene rearrangement

We report the case of a two patients who presented with a solitary, asymptomatic, angiomatoid nodule on the right thigh. Histopathological finding showed a poorly circumscribed lesion, located in the dermis. The morphological aspect strongly suggested the diagnosis of atypical fibrous histiocytoma (AFH), but surprisingly, the neoplastic cells were diffusely CD30+, with a membrane staining devoid of paranuclear dot. The lesions were tested for p80/ALK1 expression. Surprisingly, we found a diffuse cytoplasmic positivity. Interestingly, using break‐apart fluorescent in situ hybridization (FISH), we evidenced an ALK rearrangement in nearly 50% of the neoplastic cells. The expression of CD30 and ALK1 with ALK gene rearrangement raised the possibility of three diagnoses: a primary cutaneous anaplastic large cell lymphoma (ALCL), a cutaneous inflammatory myofibroblastic tumor (IMT), an AFH of the skin associated with ALK gene rearrangement and CD30 positivity. The three hypotheses were discussed and finally, although p80/ALK1 expression and cytogenetic abnormalities in fibrous histiocytoma (FH) are not yet reported to the best of our knowledge, we favored the diagnosis of AFH.     

Palisading cutaneous fibrous histiocytoma

We report 6 cases of an unusual variant of cutaneous fibrous histiocytoma in which nuclear palisading is a prominent feature. The lesions were equally distributed between males and females with a widely variable age range. Half of the cases occurred on the digits. Histopathologically, the lesions were characterized by areas of nuclear palisading with formation of Verocay-like bodies in addition to the more typical features of the "fibrous" variant of cutaneous fibrous histiocytoma. The differential diagnostic features between these lesions and those of other tumors in which nuclear palisading is seen are discussed.     

A case of malignant fibrous histiocytoma

A case of malignant fibrous histiocytoma is reported. Due to the histological features of cellular pleomorphism and myxoid degeneration seen also in other soft tissue sarcomas (rhabdomyosarcoma, liposarcoma), differential diagnosis was difficult. However, electron microscopic studies led to a distinct diagnosis of malignant fibrous histiocytoma.     

Malignant fibrous histiocytoma arising from chronic ulcer

A patient had malignant fibrous histiocytoma that developed in a chronic ulcer. Squamous cell carcinoma can develop on long-standing ulcers, but malignant fibrous histiocytoma developing in an ulcer is extremely rare.     

Benign cellular fibrous histiocytoma with erosion of the phalanx

Fibrohistiocytic tumors are characterized by the presence of fibroblast like spindle cells and histiocytes. The benign fibrous histiocytoma (dermatofibroma, BFH) as well as the malignant dermatofibrosarcoma protuberans (DFSP) and the malignant fibrous histiocytoma (MFH) belong to this group. A recurrent painful, hard 2 cm tumor on the left hallux of a 54-year-old woman led to an erosion of the underlying phalanx. The patient had suffered from ingrown toenails for more than 10 years. Histologically there was a deep penetrating fibrohistiocytic tumor that grew in a storiform pattern with interspersed foam cells. The tumor was CD34 negative and mitoses were scarce. The diagnosis was benign cellular fibrous histiocytoma (BZFH). BZFH belong to the group of BFH with a high recurrence rate especially after incomplete removal. Damage to the underlying bone has not been reported so far.     

Giant aneurysmal benign fibrous histiocytoma (dermatofibroma)

Aneurysmal benign fibrous histiocytomas are variants of dermatofibromas. These benign blood‐filled lesions can mimic malignancies due to their rapid and recurrent growth. Our patient is a 42‐year‐old Caucasian female with a past medical history of morbid obesity, diabetes, and hypertension, who presented with a mass on her left shoulder for 5 years’ duration. The mass oozed occasionally and would appear to regress but then recur replaced with progressively larger masses. Upon inspection, the patient had a large pedunculated exophytic mass with vascularity. The mass was surgically removed under general anesthesia via wide local excision. Grossly, the excised skin was purple‐tinged with an underlying fungating solid mass measuring 8.5 cm. Serial sections revealed a hemorrhagic, spongy, and granular cut surface. Histologically, the epidermis was hyperplastic, with underlying hyaline collagen bundles. The remainder of the mass was chronically inflamed and composed of spindled histiocytes, hemosiderin‐laden macrophages, and blood‐filled spaces lacking an endothelial lining. There was focal pleomorphism but no significant atypia. Immunohistochemical stains were strongly positive for vimentin and negative for CD31, CD34, and desmin. The overall architecture and immunophenotype are consistent with the diagnosis of aneurysmal benign fibrous histiocytoma.     

Benign fibrous histiocytoma of the eyelid with an unusual clinical presentation

Benign fibrous histiocytoma is a common soft tissue tumor that can be deep or superficially located. Although the deep type of fibrous histiocytoma has a predilection for the orbit, the eyelids are an unusual location for the cutaneous type. A 42-year-old woman had bilateral yellowish nodular masses of the eyelids for two years. Pathological examination after excision revealed benign fibrous histiocytoma. Our case is an unusual clinical presentation of cutaneous fibrous histiocytoma as well as a rare location such as the eyelids.     

Benign fibrous histiocytoma with osteoclast-like giant cells in an infant

Abstract:  Benign fibrous histiocytoma is a common soft tissue tumor that usually occurs in adults and is relatively rare in childhood. This report describes a 7-month-old Caucasian boy with an enlarging firm congenital nodule on his occipital scalp. Histologic analysis revealed a benign fibrous histiocytoma with osteoclast-like giant cells. Benign fibrous histiocytoma with osteoclast-like giant cells is a rare histologic variant.     

Pedunculated hemangiopericytoma-like tumor: peculiar fibroepithelial polyp or fibrous histiocytoma variant

Abstract:  Pathologists are continually challenged with the difficult task of discriminating between innocuous disease processes and potentially malignant entities. Apropos of this concern, we present a series of three cutaneous polypoid lesions that simulated fibroepithelial polyp, yet upon close scrutiny yielded histologic features of solitary fibrous tumor (SFT) or hemangiopericytoma. These pedunculated lesions showed a storiform pattern of spindled cells with interspersed gaping vascular channels reminiscent of SFT or hemangiopericytoma. Interestingly, the immunohistochemical staining profile of these lesions was negative for CD34 and positive for bcl-2 and factor XIIIa. These findings were discordant with SFT and suggest a relationship with fibrous histiocytoma. We propose that this entity represents a hitherto described variant of fibrous histiocytoma known as pedunculated hemangiopericytoma-like fibrous histiocytoma.     

Postirradiation malignant fibrous histiocytoma

A slowly growing, firm, asymptomatic tumor developed in the skin overlying the left scapula of a 72-year-old woman during a six-month period. Twenty-seven years earlier, she had radiation treatment to that site for an intraductal carcinoma of the left breast. The histopathologic diagnosis was malignant fibrous histiocytoma (MFH). The rarity of this late complication of radiation therapy is reflected by a few reports in the medical literature of cutaneous MFH as late radiation sequelae.     

Aneurysmal (angiomatoid) fibrous histiocytoma

We report a patient with aneurysmal (angiomatoid) fibrous histiocytoma manifested clinically as a single firm subcutaneous nodule, diagnosed as an epithelial cyst. Histologically, the growth showed massive histiocytic proliferation and areas with a vascular component. The lesion was histologically mistaken for Kaposi's sarcoma.     

Cholesterotic fibrous histiocytoma. Its association with hyperlipoproteinemia

A 63-year-old woman with fibrous histiocytomas showed cholesterol deposition in the setting of type IIB hyperlipidemia. The two lesions involved the left leg and right thigh. One had typical features of a fibrous histiocytoma including changes of the overlying epidermis. The other was essentially replaced by cholesterol deposits and could not be differentiated from a tuberous xanthoma. This case illustrates the histiocytic response of fibrous histiocytomas to a hyperlipoproteinemic microenvironment.     

The value of immunohistochemistry in atypical cutaneous fibrous histiocytoma

Atypical cutaneous fibrous histiocytoma is a rare variant of dermatofibroma/fibrous histiocytoma characterized by striking atypia, thus resembling atypical fibroxanthoma. We studied 9 examples of ACFH histopathologically and immunohistochemically to investigate the nature of these atypical cells. Histology revealed ill-defined skin nodules, which were polypoid in 6 cases. A minority of mononuclear and giant cells (< 5%) revealed striking pleomorphism and showed large nuclei with prominent nucleoli. Immunohistologically, the atypical cells expressed vimentin, but were negative for S-100 protein, the keratin marker MNF116, alpha smooth muscle actin, CD34, factor XIIIa, and monocyte/macrophage markers Ki-M1p, KP1 (CD68), and MAC387. Positivity for MiB1 was very modest (< 1%) and limited to small- and medium-sized, inconspicuous cells. Multinucleate giant cells proved to be heterogenous, on one hand cells with differentiation toward macrophages with positivity for Ki-M1p and KP1, on the other toward fibroblasts positive for vimentin only. These immuno-histochemical results for differentiation markers in atypical cutaneous fibrous histiocytoma are similar to our previous findings and data in atypical fibroxanthoma; MiB1 helps to separate these entities from each other as the latter shows a very high proportion of proliferative atypical cells corresponding to the numerous mitoses seen in routine sections.