Desmoplastic fibroblastoma: a case presenting as a protruding nodule in the dermis

Desmoplastic fibroblastoma is a rare, benign, soft tissue tumor. We describe a case of superficial desmoplastic fibroblastoma presenting as a protruding nodule. A 41-year-old woman presented with a painless, firm, elevated nodule with ulceration on her left thigh. Histological examination from total excision showed a well-circumscribed tumor in the dermis, which comprised of spindle, oval and stellate cells arranged in a haphazard fashion, accompanied by abundant collagenous stroma and inconspicuous vasculature. Immunohistochemically, the tumor cells were positive for vimentin, and focally positive for alpha-smooth muscle actin and muscle-specific actin, but negative for CD34, S-100 protein, desmin and beta-catenin. We diagnosed this case as desmoplastic fibroblastoma arising in the dermis and superficial subcutaneous tissue.     

Desmoplastisches Fibroblastom bei einer 22-jährigen Patientin im Bereich des Oberarms

Desmoplastic fibroblastoma (“collagenous fibroma”) is a rare benign, slowly progressive fibrous soft tissue tumor that ranges 1–20 cm in size. The tumor occurs in all ages, predominantly in the upper part of the body. Children are rarely affected. The tumor often infiltrates the subcutis; less often it invades the fascia and skeletal muscle or causes bone erosions. Histologically, the tumor is composed of spindle-shaped cells embedded in a densely collagenous stroma, sometimes forming a pseudo-capsule. Magnetic resonance imaging and computed tomography as well as ultrasonography are used to define the extensions of the tumor. Because it is clinically extremely difficult to determine if soft tissue tumors are benign or malignant, all should be excised with a margin of safety and examined histologically. We report a 22-year old woman with desmoplastic fibroblastoma located on the upper arm. Clinical and histopathological findings and treatment options are discussed.     

Desmoplastic Fibroblastoma of the Scalp Accompanied by Severe Pain; Unusual Location and Symptom

Desmoplastic fibroblastoma is a rare fibrous tumor that usually presents as a painless, slow-growing mass in the subcutaneous tissues and skeletal muscles. It has a wide anatomic distribution, with the most common involvement being the arm and shoulder. Here, we report a case of a tiny painful desmoplastic fibroblastoma arising on the scalp. According to a microscopic examination, this tumor was composed of spindle-shaped fibroblasts in the dense collagenous stroma. On immunohistochemical staining, tumor cells were positive for vimentin and negative for smooth muscle actin, CD34, and S100. Our case is unique in that desmoplastic fibroblastoma developed on the scalp and there was presence of pain despite its small size.     

Giant cell fibroblastoma: an immunohistochemical study

Giant cell fibroblastoma is a rare, benign soft tissue tumor occurring in childhood. A 34-year-old woman presented with a giant cell fibroblastoma involving the chest wall. Histologic features include an infiltrating spindle-cell tumor involving the dermis and subcutaneous fat containing characteristic sinusoidal spaces rimmed by spindle cells and multinucleate giant cells. Immunohistochemical studies support a fibrohistiocytic differentiation.     

Giant cell fibroblastoma. A report of a case and review of the literature

A 15-year-old white boy with a giant cell fibroblastoma of the skin of the abdomen is described. Giant cell fibroblastoma is a rare soft tissue neoplasm that most commonly occurs in children as a small, painless mass in the dermis and subcutaneous tissue. Although local recurrences have been reported, no metastases have occurred. Giant cell fibroblastoma must be differentiated from other spindle cell neoplasms.     

Desmoplastic fibroblastoma (collagenous fibroma).

Desmoplastic fibroblastoma is a vary rare subcutaneous proliferation. We describe a case of desmoplastic fibroblastoma in a 24-year-old Korean woman who presented with a 2.5 cm solitary and firm nodule on her back which had been present for 3 months. Histologic studies showed a well demarcated subcutaneous tumor composed of stellate or spindle shaped cells embedded in hypovascular fibrous or fibromyxoid stroma. No mitotic figures, calcification, or necrosis were observed. The stellate or spindle shaped cells were positive for vimentin. The stroma stained positively with Alcian blue and Masson trichrome. S-100 protein, actin, desmin, and elastic fiber stains were all negative in the stellate or spindle shaped cells. There has been no recurrence or metastasis of the tumor over an 18-month follow-up.     

Desmoplastic trichoepithelioma: report of a case illustrating its natural history

First described more than 30 years ago, desmoplastic trichoepithelioma is a rare but benign adnexal neoplasm. Most often identified in middle-aged individuals and females, desmoplastic trichoepithelioma usually is a solitary annular plaque. Though the tumors are benign, the possibility of malignant neoplasm may spark both clinical and histologic concern. A full-thickness skin biopsy is advisable when desmoplastic trichoepithelioma is suspected. A patient's clinical history may provide some clues to help guide diagnosis, as the tumors may be present for years and slow growth is commonly reported. We present a patient with desmoplastic trichoepithelioma that uniquely documents and supports the typical natural history of this tumor, as demonstrated by annual school photographs.     

Desmoplastic trichoepithelioma: presentation of two cases

Trichoepithelioma is a benign neoformation with hair follicle differentiation that may clinically present in solitary, multiple or desmoplastic form. From a histopathological standpoint, it poses some diagnostic difficulties with basal cell carcinoma. We present two cases of desmoplastic trichoepithelioma, a rare adnexal tumor whose incidence is estimated at 2 per 10,000. Desmoplastic trichoepithelioma is a benign lesion, clinically and histologically similar to other dermatoses, and presents a true diagnostic challenge.     

Linear trichilemmomas on the ankle of a 28‐year‐old female

Trichilemmomas are benign cutaneous proliferations derived from the outer root sheath of the hair follicle. They most often occur on the head and neck region and show a female predominance. When multiple, they are associated with Cowden syndrome (CS), a rare disorder due to an autosomal dominant germline mutation in PTEN (phosphatase and tensin homolog on chromosome 10), a tumor suppressor gene. Trichilemmomas outside of the head and neck region are rare, and as such, the association with CS is not clear. A 28‐year‐old healthy female with no significant family history of cancer presented to her dermatologist with multiple erythematous papules on the left anterior ankle, starting at birth. A shave biopsy confirmed the diagnosis of trichilemmoma with focal desmoplastic features (or desmoplastic trichilemmoma). A PTEN immunohistochemical study showed patchy (but not complete) loss of staining of the lesional cells. After shave removal, the trichilemmomas recurred 1–2 months later.     

Cutaneous and subcutaneous fibrohistiocytic tumors of intermediate malignancy: an update

The fibrohistiocytic tumors of intermediate malignancy are uncommon mesenchymal tumors, which typically occur in the skin and subcutis and which may pose significant problems for the dermatopathologist. This article reviews the clinical, histopathologic, and genetic features of dermatofibrosarcoma protuberans, giant cell fibroblastoma, angiomatoid (malignant) fibrous histiocytoma, plexiform fibrous histiocytoma, and soft tissue giant cell tumor (of low malignant potential). The differential diagnosis of these tumors with a variety of benign and fully malignant cutaneous soft tissue neoplasms is discussed.     

Imiquimod as an Adjuvant Treatment Measure for Desmoplastic Trichoepithelioma

Desmoplastic trichoepithelioma is a rare benign adnexal tumor. Although it is a benign lesion, patients often want to treat it due to cosmetic concerns when it occurs in an easily visible site. For our two cases, topical 5% imiquimod was an attractive treatment option as it is applied by the patients themselves and it has minimal side effects, including leaving no scar. However, the lesions recurred after clinical remission. To the best of our knowledge, this is the only report on utilizing imiquimod to treat a benign adnexal tumor, and especially desmoplastic trichoepithelioma.     

IMP‐3 expression in melanocytic lesions

Background: Insulin‐like growth factor‐II mRNA‐binding protein 3 (IMP‐3 ), a member of the insulin‐like growth factor mRNA‐binding protein family, is expressed in several human malignancies, including melanomas. However, the expression of IMP‐3 has not been explored in melanoma in situ, various histologic subtypes of invasive melanomas and atypical Spitz tumors. Methods: IMP‐3 immunostain was performed in 157 melanocytic lesions. Results: Nearly all benign (8/8), dysplastic (8/8) and Spitz nevi (8/9) were negative for IMP‐3. Focal IMP‐3 positivity was observed in 5/12 melanoma in situ and 4/15 superficial melanomas (Breslow depth ≤1 mm). Half (10/20) of deep melanomas (Breslow depth >1 mm) and 25/52 metastatic melanomas demonstrated strong IMP‐3 staining. IMP‐3 expression differs significantly between non‐desmoplastic melanomas (superficial and deep) and benign or dysplastic or Spitz nevi (p = 0.0427, respectively). Four of 23 desmoplastic melanomas expressed IMP‐3 , which was significantly different from deep melanomas (p = 0.0109). IMP‐3 stained 7 of 10 atypical Spitz tumors. The difference between atypical Spitz tumors and Spitz nevi was statistically significant (p = 0.0256). Conclusion: A malignant circumstance, such as non‐desmoplastic melanoma or atypical Spitz tumor, can be inferred when IMP‐3 is expressed, suggesting potential diagnostic value of IMP‐3 in melanocytic lesions. Yu L, Xu H, Wasco MJ, Bourne PA, Ma L. IMP‐3 expression in melanocytic lesions.     

Angiomatoid and desmoplastic Spitz nevus presenting as a keloidal nodule

Angiomatoid and desmoplastic Spitz nevi are rare histologic variants of Spitz nevi that present most frequently on the extremities of children and young adults. Although Spitz nevi are clinically heterogeneous, one presenting as a keloidal nodule has not been previously published. We present a case of an angiomatoid and desmoplastic Spitz nevus clinically akin to a keloid on an African‐American teenager and describe its unique histopathologic features.     

Fibroblastoma de células gigantes inguinal

—Giant cell fibroblastoma is a rare mesenchymal neoplasm of unknown origin, occurring mostly in the two first decades of life. Although it often pursues a locally recurrent course, there has been no confirmation of metastatic capability. We report the case of a six year old boy attended at our Service presenting a tumour in the left groin, which developed over a scar, suggestive of cheloid. A lesion was surgically removed in this area and diagnosed as a giant cell fibroblastoma, two months ago.A skin biopsy was performed and revealed a local recurrence of giant cell fibroblastoma.We review the clinical manifestations, histological findings and histogenesis of this tumour, and the different therapeutical options.     

Congenital Atrophic Plaque: Fibroblastic Connective Tissue Nevus

Fibroblastic connective tissue nevus (FCTN) is a rare, benign, dermal mesenchymal hamartoma that affects children. We report a 15‐year‐old boy with a congenital FCTN and describe the clinical, dermatoscopic, and histopathologic features.     

Giant cell fibroblastoma in a child misdiagnosed as a dermatofibroma

We report a 9-year-old African-American boy with a giant cell fibroblastoma of the shoulder that was incorrectly diagnosed as a keloid and dermatofibroma. Initial misdiagnosis led to a delay of 4 years in the correct diagnosis, with the tumor producing significant local destruction. We review herein the clinical manifestations, histologic findings, histogenesis, relationship to dermatofibrosarcoma protuberans (DFSP), treatment, and differential diagnosis of giant cell fibroblastoma (GCF). This information is important in correctly diagnosing this uncommon, benign, but locally aggressive and recurrent tumor of childhood. The clinician should consider GCF and DFSP when the pathologic diagnosis of dermatofibroma is made in lesions more than 2 cm in diameter, or when this diagnosis is made in a prepubertal child.     

Medallion‐like dermal dendrocyte hamartoma: A rare congenital CD34‐positive dermal lesion clinically and pathologically overlapping with fibroblastic connective tissue nevus

Both medallion‐like dermal dendrocyte hamartoma and fibroblastic connective tissue nevus are rare benign dermal lesions composed of CD34‐positive spindle cells. Although regarded as different diseases, it is sometimes difficult to distinguish between them due to their clinical and pathological similarities. We present a case of medallion‐like dermal dendrocyte hamartoma that could also be diagnosed as fibroblastic connective tissue nevus and propose the possibility of overlap in these diseases.     

Subungual Soft Tissue Chondroma with Nail Deformity in a Child

Soft tissue chondroma is a rare benign tumor of the cartilage. It occurs commonly in distal extremities of middle‐aged patients. It is usually asymptomatic and grows slowly, making early diagnosis difficult. We report a 10‐year‐old patient with a 1‐year history of a subungual soft tissue chondroma on her left fifth finger. The lesion arose from nail bed and distal nail matrix, resulting in nail dystrophy. Magnetic resonance imaging revealed a soft tissue tumor in the subungual region and soft tissue chondroma was diagnosed, based on histopathologic findings. Dermatologists should consider soft tissue chondroma in the differential diagnosis of subungual tumors of children.     

Superficial malignant peripheral nerve sheath tumor with overlying intradermal melanocytic nevus mimicking spindle cell melanoma

Malignant peripheral nerve sheath tumors are rare soft tissue sarcomas with histological and immunohistochemical similarities to spindle cell melanoma. Although spindle cell melanoma is significantly more common, both tumors may express S100 and lack staining for HMB‐45, Melan‐A or MITF. Here we present a case of superficial malignant peripheral nerve sheath tumor with diffuse S100 positivity arising in a subtle neurofibroma in close proximity to an intradermal melanocytic nevus. This configuration had led to prior misdiagnosis as a desmoplastic melanoma arising in the nevus and to sentinel lymph node biopsy. Identification of the background neurofibroma, as well as CD34 positivity raised consideration of a low grade malignant peripheral nerve sheath tumor, which was confirmed via observation of Schwannian differentiation on electron microscopy. The importance of distinguishing these two tumors is stressed owing to the difference in management.     

Desmoplastic sebaceoma arising from nevus sebaceus: a new variant

Nevus sebaceus is known to have the potential to develop into various secondary tumors. We observed a sebaceoma arising from a nevus sebaceus excised from the left cheek of a 51‐year‐old woman. This sebaceoma showed desmoplastic change similar to that observed in desmoplastic trichoepithelioma and desmoplastic trichilemmoma. This heretofore undescribed desmoplastic variant of sebaceoma should not be mistaken for invasive sebaceous carcinoma.