From the Guidelines
Cellular fibrohistiocytoma should be treated with complete surgical excision with clear margins, as this approach is usually curative with a low recurrence rate. This recommendation is based on the general principles of managing soft tissue tumors, as outlined in the UK guidelines for the management of soft tissue sarcomas 1. Although the guidelines do not specifically address cellular fibrohistiocytoma, they emphasize the importance of accurate diagnosis and treatment of soft tissue tumors to prevent local aggression and improve quality of life.
Key characteristics of cellular fibrohistiocytoma include:
- A firm, slow-growing nodule in the skin, most commonly on the extremities
- A mixture of fibroblasts and histiocytes arranged in a storiform or whorled pattern
- A higher density of cells compared to conventional dermatofibromas
- Positive results for factor XIIIa and negative for CD34 on immunohistochemical staining, which helps differentiate it from more concerning entities
It is essential to distinguish cellular fibrohistiocytoma from more aggressive tumors, such as dermatofibrosarcoma protuberans, to ensure appropriate treatment and follow-up. The UK guidelines 1 recommend a comprehensive diagnostic workup, including imaging studies and histopathological examination, to guide treatment decisions. In the case of cellular fibrohistiocytoma, complete surgical excision with clear margins is the recommended treatment, with regular follow-up to monitor for recurrence.
From the Research
Definition and Characteristics
- Cellular fibrohistiocytoma is a distinct variant of fibrous histiocytoma, first described in 1994 2
- It is considered a rare and poorly documented tumor, with a high risk of local recurrence and low but serious metastatic potential 3
Clinical Presentation
- The tumor can occur on various parts of the body, including the extremities, head and neck, and trunk 4
- It is typically composed of a polymorphous population of bland spindle and histiocytoid cells in a mixed storiform and fascicular growth pattern 5
- Histologic variants include cellular, aneurysmal, atypical, and epithelioid types 5
Treatment and Prognosis
- Complete excision and clinical follow-up are recommended, with chest x-rays and ultrasound examination of regional lymph nodes performed in atypical lesions 2
- Wide surgical resection and close follow-up, including chest x-rays or thorax computed tomography (CT), are recommended in all cellular fibrohistiocytoma cases with local recurrence 3
- The prognosis is generally poor in cases with metastasis, with a median time to death of 64 months 5
Metastasis and Recurrence
- Metastasis can occur in rare examples, involving the lungs, lymph nodes, soft tissues, and liver 5
- Local recurrence is common, with a time to first recurrence ranging from 6 weeks to 13 years 5
- Distant metastasis can occur after repeated recurrences, with bilateral pulmonary metastases reported in one case 4
Diagnosis and Differential Diagnosis
- Immunophenotyping can be performed to aid in diagnosis, with variable expression of alpha smooth muscle actin and CD34 positive cells 4
- Increased awareness of the clinocopathological features and immunophenotypes of cellular fibrohistiocytoma is helpful in avoiding misdiagnosing the disease as malignant tumors, especially dermatofibrosarcoma protuberans 4