Cellular Dermatofibroma: A Comprehensive Review

Introduction

Dermatofibroma, also known as benign fibrous histiocytoma, is a common cutaneous lesion. Cellular dermatofibroma is a less frequent, yet clinically significant, variant. First described in the late 20th century, cellular dermatofibroma is defined by its increased cellularity, fascicular growth pattern, and occasionally, deep extension into subcutaneous tissue. These features can mimic malignant soft tissue tumours such as dermatofibrosarcoma protuberans (DFSP) and leiomyosarcoma, necessitating careful evaluation.

The clinical significance of cellular dermatofibroma lies in its potential for misdiagnosis, which may lead to overtreatment or, conversely, under-recognition of a more aggressive neoplasm. Understanding its epidemiology, presentation, histopathology, and management is therefore crucial for clinicians, pathologists, and dermatologists.

Epidemiology

Cellular dermatofibroma constitutes approximately 5% of all dermatofibromas. Dermatofibromas in general are among the most common benign skin tumours, with prevalence estimates ranging from 0.1% to 3% in the adult population. Cellular variants are less common but are increasingly recognised due to heightened awareness and improved diagnostic techniques.

Demographics: Dermatofibromas, including cellular types, are most frequently observed in adults between the ages of 20 and 50 years. There is a slight female predominance, with a female-to-male ratio reported between 2:1 and 4:1. This gender disparity is thought to be related to hormonal influences, although conclusive evidence is lacking.

Risk Factors: The exact aetiology of cellular dermatofibroma remains uncertain. Some studies suggest a history of minor trauma or insect bites as potential triggering factors, possibly leading to a reactive proliferation of fibroblasts and histiocytes. Genetic predisposition has not been definitively established. Immunosuppression does not appear to be a significant risk factor in the development of this lesion.

Clinical Features

Cellular dermatofibroma typically presents as a solitary, slow-growing, firm nodule. The lesion is usually asymptomatic, although some patients may report mild tenderness or pruritus.

• Location: Most commonly observed on the lower extremities, particularly the legs, but can occur on the arms, trunk, and rarely, the head and neck region.
• Size: Cellular dermatofibromas tend to be larger than conventional dermatofibromas, often exceeding 2 cm in diameter. Lesions up to 5 cm have been reported.
• Appearance: The lesion is typically well-circumscribed, dome-shaped, firm, and may be hyperpigmented or flesh-coloured. The overlying epidermis can be normal, atrophic, or display peripheral hyperpigmentation. Dimpling or retraction of the skin upon lateral compression (the “dimple sign”) is commonly noted.
• Symptoms: Usually asymptomatic. Pain or tenderness may occur if the lesion is traumatised or inflamed.
• Growth Pattern: While growth is typically slow, some cellular dermatofibromas may exhibit more rapid enlargement compared to classical variants, contributing to diagnostic uncertainty.

Multiple lesions are rare but have been described, particularly in patients with underlying immune dysfunction. However, the vast majority are solitary.

Histopathology

Histopathological examination remains the gold standard for diagnosis. Cellular dermatofibroma is distinguished from conventional dermatofibroma by several key features:

• Cellularity: As the name suggests, there is a marked increase in cellularity, with sheets and fascicles of spindle-shaped fibroblastic and histiocytic cells.
• Growth Pattern: Fascicular or storiform growth is prominent. The lesion often extends into the reticular dermis and may invade the subcutaneous fat in a wedge-shaped configuration.
• Mitotic Activity: Mitotic figures are more frequent than in classic dermatofibroma but should not display atypical forms. The presence of atypical mitoses or significant cytological atypia raises concern for sarcoma.
• Collagen Trapping: Entrapment of thickened collagen bundles at the periphery is a characteristic finding.
• Epidermal Changes: Overlying epidermis may show acanthosis, hyperpigmentation of the basal layer, or atrophy.
• Inflammatory Infiltrate: Variable lymphocytic infiltrate, often perivascular, is commonly observed.
• Immunohistochemistry: Cells are typically positive for factor XIIIa and negative for CD34, which helps distinguish cellular dermatofibroma from DFSP (which is usually CD34-positive and factor XIIIa-negative). Other markers such as smooth muscle actin (SMA) may show focal positivity.

The distinction from malignant spindle cell tumours is paramount, as misinterpretation can result in unnecessary aggressive management.

Differential Diagnosis

The clinical and histopathological overlap between cellular dermatofibroma and other fibrohistiocytic or spindle cell neoplasms necessitates a careful and methodical approach to differential diagnosis.

• Dermatofibrosarcoma Protuberans (DFSP): DFSP is a locally aggressive, low-grade sarcoma that can resemble cellular dermatofibroma both clinically and histologically. Key distinguishing features include:
• DFSP is usually larger, plaque-like, and fixed to underlying structures.
• Histologically, DFSP demonstrates a more uniform storiform pattern and infiltrates the subcutaneous fat in a “honeycomb” fashion.
• Immunohistochemistry: DFSP is CD34-positive and factor XIIIa-negative, the reverse of cellular dermatofibroma.
• Atypical Fibroxanthoma (AFX): Occurs mainly in sun-exposed areas of elderly patients. AFX shows more pronounced cytological atypia, pleomorphism, and atypical mitoses.
• Leiomyosarcoma: Malignant smooth muscle tumour with intersecting fascicles of spindle cells, marked atypia, and high mitotic activity. Desmin and SMA positivity assist in its identification.
• Malignant Fibrous Histiocytoma (Undifferentiated Pleomorphic Sarcoma): Shows marked pleomorphism and high mitotic activity, distinct from cellular dermatofibroma.
• Benign Lesions: Other benign lesions such as piloleiomyoma, neurofibroma, and keloid may occasionally mimic cellular dermatofibroma, but can usually be differentiated by clinical context and histology.
• Accurate diagnosis is critical to avoid both overtreatment and undertreatment. Immunohistochemistry, particularly CD34 and factor XIIIa, is invaluable for this purpose.

Treatment and Management

The management of cellular dermatofibroma is guided by its benign nature but also by the need to exclude more aggressive tumours.

Surgical Excision

Complete surgical excision with narrow margins is the treatment of choice. Excision is curative in the vast majority of cases. Margins of 1–2 mm are generally sufficient, as cellular dermatofibroma has a very low risk of recurrence or metastasis.

Indications for Excision: Diagnostic uncertainty (to rule out sarcoma or DFSP). Cosmetic concerns or symptoms such as pain or pruritus. Lesions demonstrating rapid growth or atypical features.

Procedure: Standard elliptical excision is usually adequate. Mohs micrographic surgery is rarely required but may be considered in difficult anatomical locations or for recurrent lesions.

Histopathological Assessment: All excised lesions should be submitted for histopathological analysis to confirm the diagnosis and exclude malignancy.

Non-Surgical Management

Non-surgical management is rarely indicated due to the diagnostic importance of histopathological confirmation. However, observation may be considered in selected cases where the diagnosis is certain, the lesion is asymptomatic, and there are no cosmetic concerns. Cryotherapy, laser ablation, or intralesional corticosteroids have been used for conventional dermatofibromas but are not standard for cellular variants.

Follow-up Care

Routine follow-up is generally not required after complete excision of a confirmed cellular dermatofibroma. However, patients should be advised to monitor the site for signs of recurrence and to seek medical attention if new or changing lesions develop.

Prognosis

Cellular dermatofibroma is a benign lesion with an excellent prognosis. Recurrence rates are low, typically less than 5%, and are usually attributable to incomplete excision. Malignant transformation has not been reported. There is no evidence of metastasis.

Long-term Considerations: Patients should be reassured regarding the benign nature of the lesion. Nevertheless, careful clinicopathological correlation is essential to exclude more aggressive neoplasms at the outset. In rare cases of recurrence, re-excision is curative.

Nursing Care of Patients with Cellular Dermatofibroma

Caring for patients with cellular dermatofibroma requires a holistic nursing approach that encompasses accurate assessment, patient education, wound care, psychological support, and interdisciplinary collaboration. This document explores the nuances of nursing care for patients affected by this condition.

Assessment and Initial Nursing Interventions

Comprehensive Patient Assessment

• Collect a detailed history, including duration of lesion, changes in size, color, or sensation, and any associated symptoms like pain, bleeding, or ulceration.
• Assess for risk factors, such as prior skin trauma, immune status, and family history of skin lesions or tumors.
• Perform a thorough skin examination, noting the size, number, color, and distribution of lesions.
• Document findings with photographs for monitoring changes over time.

Psychological Assessment

• Assess the patient’s emotional response to the lesion, including anxiety, embarrassment, or concern about malignancy.
• Evaluate the impact of the lesion on self-image, especially if located in visible areas such as the face or hands.

Patient Education

Nurses play a pivotal role in educating patients and their families about cellular dermatofibromas to alleviate anxiety and encourage participation in the treatment plan.

• Nature of the Lesion: Explain that the condition is benign and not contagious, although cellular dermatofibromas can occasionally recur or mimic more serious conditions.
• Prognosis: Reassure patients that cellular dermatofibroma is rarely associated with malignancy or metastasis, but surgical excision is sometimes recommended for large, symptomatic, or suspicious lesions.
• Expected Outcomes: Discuss potential outcomes of treatment, including scarring and the low risk of recurrence.
• Skin Care: Instruct on gentle skin care and signs of infection to watch for after procedures like biopsy or excision.
• Follow-Up: Emphasize the importance of monitoring the lesion and attending follow-up appointments for early detection of recurrence or complications.

Wound Care and Post-Procedure Management

After excision or biopsy, appropriate wound care is essential to promote healing and prevent complications.

Immediate Post-Procedure Care

• Monitor the wound for signs of bleeding, infection, or dehiscence.
• Apply sterile dressings as directed, and educate the patient on dressing changes.
• Provide pain management with appropriate analgesics as prescribed.
• Advise on activity restrictions to avoid trauma to the intervention site.

Long-Term Wound Care

• Encourage gentle hygiene of the affected area, avoiding harsh chemicals or abrasive scrubbing.
• Advise the use of sunscreen or protective clothing if the site is exposed to sunlight, as UV exposure may increase pigmentation or scarring.
• Monitor for delayed healing, hypertrophic scarring, or keloid formation.

Pain and Symptom Management

Pain is usually minimal but may occur post-biopsy or excision.

• Assess pain level regularly using a standardized pain scale.
• Administer medications as ordered and offer non-pharmacological comfort measures, such as ice packs or relaxation techniques.
• Educate about the transient nature of post-procedural discomfort.

Infection Prevention

Infection is an uncommon but important complication to prevent.

• Teach proper hand hygiene before and after touching the wound.
• Recognize early signs of infection: increased redness, swelling, warmth, purulent discharge, or fever.
• Instruct patients to seek medical attention if infection is suspected.

Psychosocial Support

Even benign skin lesions can have significant psychosocial impact, especially if visible or associated with scarring.

• Provide a supportive environment where patients can express concerns.
• Offer resources for counseling or support groups if needed.
• Encourage open communication with family members to foster understanding and support.

Interdisciplinary Collaboration

Optimal care often involves coordination with several health professionals.

• Dermatologists for diagnosis, excision, and follow-up care.
• Pathologists for accurate histopathological interpretation.
• Plastic surgeons if reconstructive procedures are required for extensive lesions.
• Psychologists or counselors for patients experiencing distress or body image concerns.

Special Considerations

Care for Pediatric Patients

• Use age-appropriate language to explain procedures and care requirements.
• Involve caregivers in decision-making and care practices.
• Monitor for signs of distress, anxiety, or fear related to medical interventions.

Caring for the Elderly

• Assess for comorbid conditions that may affect wound healing or increase infection risk.
• Adapt care plans to accommodate decreased mobility, vision, or dexterity.
• Provide clear instructions in large print or verbal communication as needed.

Monitoring and Follow-Up

Ongoing monitoring is crucial for early detection of recurrence or complications.

• Schedule regular follow-up visits, particularly after excision, to evaluate for regrowth or abnormal changes.
• Document changes in lesion appearance, patient-reported symptoms, and wound healing progress.
• Adjust care plans as needed based on patient response and new developments.

Patient Advocacy and Empowerment

Nurses serve as advocates by ensuring patients receive accurate information and appropriate care.

• Empower patients to ask questions and participate in care decisions.
• Clarify misunderstandings regarding the benign nature of the lesion and treatment options.
• Assist in navigating healthcare resources and insurance concerns related to dermatologic care.

REFERENCES

1. Alves JVP, Matos DM, et al. Variants of dermatofibroma – a histopathological study. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4056706/. An Bras Dermatol. 2014 May-Jun; 89(3): 472–477.
2. DermNet NZ. Dermatofibroma pathology. https://dermnetnz.org/topics/dermatofibroma-fibrous-histiocytoma-pathology/.
3. Elbendary A, Griffin JR, Elston DM, Verma S. Cellular dermatofibroma: A hyperkeratotic indurated plaque on the thigh. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4976415/. Indian Dermatol Online J. 2016 Jul-Aug; 7(4): 308–310.
4. Gaufin M, Michaelis T, Duffy K. Cellular Dermatofibroma: Clinicopathologic Review of 218 Cases of Cellular Dermatofibroma to Determine the Clinical Recurrence Rate. Dermatol Surg. 2019 Nov;45(11):1359-1364.
5. Le NT, Eisen DB. Clinical and histopathologic characteristics and outcomes of cellular dermatofibroma: A retrospective observational study of 29 patients. JAAD Int. 2025 Jan 6;19:43-44.
6. Erdil Dİ, Leblebici C, Erdil D, Manav V, Erdemir VA, Aksu AEK. Dermatofibroma: clinicopathological analysis of 239 cases. An Bras Dermatol. 2025 Jan-Feb;100(1):150-155.

Stories are the threads that bind us; through them, we understand each other, grow, and heal.

JOHN NOORD

Connect with “Nurses Lab Editorial Team”

I hope you found this information helpful. Do you have any questions or comments? Kindly write in comments section. Subscribe the Blog with your email so you can stay updated on upcoming events and the latest articles.