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.     

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.     

Primary Cutaneous Solitary Fibrous Tumor on the Back

Solitary fibrous tumors (SFT) are uncommon mesenchymal tumors. SFT have several synonyms including localized fibrous tumor, benign mesothelioma, localized fibrous mesothelioma, and submesothelial fibroma. SFT usually occur in the pleura or other serosal surfaces, but SFT can also develop in extrapleural areas including the nasal cavity, orbit, retroperitoneum, and pelvis. Cutaneous SFT is extremely rare, and more likely to occur in the head and neck region. Histologically, this tumor can mimic a variety of benign and malignant tumors such as dermatofibroma, dermatofibrosarcoma protuberans, spindle cell lipoma or other mesenchymal tumors. Most cases of SFT show non-aggressive clinical courses, with low recurrence rates. Herein, we describe a case of primary cutaneous SFT which presented with huge mass on the back.     

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.     

Progressive nodular histiocytoma

A 42-year-old male with progressive nodular histiocytoma is reported who presented with progressively increasing superficial reddish brown papules, deep cutaneous nodules and a pedunculated lesion with telangiectasia for the last 20 years. Histopathology revealed histiocytic, fibroblastic, and vascular proliferation, foam cells, occasional giant cells and iron deposit in the lesions.     

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.     

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.     

Multiple cutaneous fibrous histiocytomas in association with systemic lupus erythematosus

Cutaneous fibrous histiocytomas are usually regarded as superficial lesions and commonly known as dermatofibromas; however, unusual cases histologically showing fibrohistiocytic proliferation extending into the deeper dermis or subcutaneous tissues are occasionally experienced. Some authors propose this type as benign fibrous histiocytoma of the skin, distinct from dermatofibroma. We describe herein a case of systemic lupus erythematosus (SLE) who developed multiple nodules on the face, trunk and extremities. The nodule on the forehead did not present a typical clinical appearance of dermatofibroma, and histopathological examination showed fibrohistiocytic proliferation with a storiform pattern extending into the deep dermis and subcutaneous tissues. By contrast, histology of the nodule on the abdomen showed fibrohistiocytic proliferation confined to the dermis and compatible with dermatofibroma. Although multiple dermatofibromas are occasionally seen in patients with SLE, benign fibrous histiocytoma of the skin showing deeper invasion than dermatofibroma is rarely associated with SLE.     

Benign fibrous histiocytoma (dermatofibroma) of the face: clinicopathologic and immunohistochemical study of 34 cases associated with an aggressive clinical course.

Thirty-four cases of fibrous histiocytoma (dermatofibroma) arising on the face are reported. These neoplasms occurred frequently in females (24 female, 10 male) and showed a broad age range (12 to 85 years; mean: 43.6 years, median: 41 years). The neoplasms originated on the forehead (nine cases), the cheek (eight cases), the eyebrow (four cases), the temporal region (three cases), the nose (two cases), and the ear (one case); in seven cases the location face was given only. Five of 27 cases with follow-up information (median: 5 years) recurred locally; in one case four recurrences were excised within 8 years. The majority of cases extended into the subcutis and deep soft tissue including striated muscle (50% of cases). Histologically, only the minority of cases was composed entirely of histiocytoid and spindle-shaped tumor cells arranged in a storiform growth pattern. In many cases cellular fascicles and bundles of spindle-shaped tumor cells were noted in addition to classical morphological features of fibrous histiocytoma. A moderate mitotic rate (mean: 2.97 mitoses in 10 HPFs) was observed, and in few cases increased atypia was evident. Frank tumor necrosis and/or vascular invasion were not identified. Immunohistochemical studies revealed Factor XIIIa positivity in 13 out of 17, focal CD68 positivity in 6 out of 10, and alpha-smooth muscle actin positivity in 16 out of 19 cases tested. These lesions should be distinguished from dermatofibrosarcoma protuberans, including its fibrosarcomatous variant, leiomyosarcoma, and low-grade myofibroblastic sarcoma. Cases of fibrous histiocytoma of the face have to be excised with wider margins in comparison with examples of classical fibrous histiocytoma occurring on the extremities because of diffuse infiltration, involvement of deeper structures, and an increased rate of local recurrences.     

Epithelioid cell histiocytoma with underlying artery damage

Although epithelioid cell histiocytoma is considered a variant of fibrous histiocytoma (dermatofibroma), the histogenesis of this condition remains controversial. A recent investigation suggested the possibility that epithelioid cell histiocytoma is an angioformative fibrous histiocytoma. We report a case of epithelioid cell histiocytoma underlying a damaged artery. This epithelioid cell histiocytoma with a central area of hemorrhage was associated with a medium-sized artery in the reticular dermis running vertically up to the lesion. Both the artery in the reticular dermis and its centrally branched artery in the subcutaneous tissue showed mural injury and intraluminal epithelioid endothelial proliferation. Immunohistochemically, the labeling rate for each of the antibodies studied in the epithlioid cells was as follows: 40% for Factor XIIIa, 5% for CD34, 20% for factor VIII-related antigen, and 10% for alpha-smooth muscle cell actin. This case may support the view that epithelioid cell histiocytoma is a vascular and angioformative fibrous histiocytoma.     

Subcutaneous solitary fibrous tumor

We describe a unique case of subcutaneous solitary fibrous tumor (SFT) in a 56-year-old female patient. The patient had been aware of a painless soft mass in her back for ten years. The lesion was surgically excised. Histological examination revealed that the well-defined mass was composed of a proliferation of spindle-shaped fibroblastic cells and polygonal cells embedded in a fibrous matrix corresponding to the so-called "patternless pattern". A prominent pericytomatous pattern (hemangiopericytoma-like structures), focal myxoid changes, and thick hyalinized collagen fibers were also observed. Immunohistochemical stainings for CD34 and bcl-2 were positive in the tumor cells. These features are compatible with SFT. We suggest that SFT should be included in the differential diagnosis of subcutaneous spindle cell tumors.     

Solitary fibrous tumor of the vagina

We report of a solitary fibrous tumor (SFT) of the vagina and discuss the differential diagnosis. This is the first SFT documented, to our knowledge. SFTs should be included in the differential diagnosis of fibroblastic, myofibroblastic, and neural lesions of the skin, subcutaneous tissue, and mucosa and can be distinguished from other spindle cell neoplasms at those sites.     

Fibrohistiocytic skin tumors

The fibrohistiocytic tumors of the skin are a heterogeneous group of dermal/subcutaneous mesenchymal neoplasms which show fibroblastic, myofibroblastic and histiocytic (macrophage‐like) differentiation, often one beside the other in the same tumor. “Fibrohistiocytic” means in this context the morphologic similarity of the cells with fibroblasts and histiocytes. The WHO classification of 2005 includes the following entities as fibrohistiocytic tumors of the skin: Benign: 1. Fibrous histiocytoma (FH)/(synonymous: Dermatofibroma. Variants of FH: 1a. cellular fibrous histiocytoma, 1b. atypical (pseudosarcomatous) fibrous histiocytoma, 1c. aneurysmatic fibrous histiocytoma, 1d. epithelioid fibrous histiocytoma; 2. dermatomyofibroma; 3. (juvenile) xanthogranuloma. Intermediate: 4. plexiform fibrohistiocytic tumor; 5. dermatofibrosarcoma protuberans; 6. atypical Fibroxanthoma. Malignant: 7. malignant fibrous histiocytoma. All these entities are reviewed in this paper with particular attention devoted to differential diagnostic considerations.     

Dermatofibroma with monster cells

Nineteen cases of dermatofibroma associated with monster cells are reported. The term "monster" (an animal with a strange or terrifying shape, one unusually large for its kind) implies a strikingly atypical cell with an extremely large nucleus. Except for monster cells, these 19 lesions had all of the typical histopathological findings of dermatofibroma. The clinical diagnosis for 16 of these lesions was dermatofibroma (or histiocytoma). Three lesions were submitted without any clinical diagnosis. Eighteen of 19 lesions occurred on the extremities. One was on the back. Monster cells are seen in the early, histiocytic stage of dermatofibroma when lipophages and/or siderophages are usually present in large numbers. Only rarely were mitotic figures seen in dermatofibromas with monster cells, and they were neither numerous nor atypical. It is important for histopathologists to distinguish dermatofibroma with monster cells from cutaneous malignant fibrous histiocytoma and radiation sarcoma. The criteria for differentiation concern primarily the architectural pattern of the lesion rather than its cytological features.     

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.     

Aneurysmal Benign Fibrous Histiocytoma with Atrophic Features

Aneurysmal benign fibrous histiocytoma is an uncommon pathologic variant of dermatofibroma. In addition to the features of a typical dermatofibroma, it has large cleft-like or cavernous blood-filled spaces with numerous hemosiderin pigments. It should be differentiated from angiomatoid malignant fibrous histiocytoma, malignant melanoma, and vascular tumors such as Kaposi''s sarcoma and angiosarcoma. Atrophic dermatofibroma is also a rare variant of dermatofibroma, and the combination of aneurysmal and atrophic features is rarer still. We report a case of aneurysmal benign fibrous histiocytoma with atrophic features in a 27-year-old male who had a grayish-brown atrophic patchy lesion on his back for 2 years.     

Agminated histiocytomas in a 23-year-old patient

A 23-year-old patient presented with a group of 17 reddish-brown papules and nodules on the left shoulder lasting for 4 years. The histopathologic examination after a punch biopsy was repetitively consistent with the diagnosis of fibrous histiocytoma (FH). We use the term agminate histiocytomas for the first time to stress the presence of grouped lesions in one skin segment. Intralesional corticosteroids and cryotherapy were partially successful in this patient.     

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.     

Benign fibrous histiocytoma of the foot: a literature review and case report

A rare case of benign fibrous histiocytoma involving the foot of a sixty-three-year-old white man is presented, with a review of the literature. The histopathologic appearance of benign fibrous histiocytoma, differential diagnosis, and surgical management are discussed. Fibrous histiocytomas are characteristically nonencapsulated tumors composed of a mixture of fibroblastic and histiocytic cells arranged in a storiform or cartwheel pattern.