There are a variety of benign dermal and subcutaneous tumors that present to the procedural dermatologist for management. We provide an overview of the epidemiology, clinical presentation, differential diagnosis, histopathology, and surgical management of each of these tumors, and discuss the surgical management of these lesions.
Lipomas are a common benign neoplasm composed predominantly of lobules of mature adipocytes and fibrous stroma.1 They are found most often in the subcutaneous tissue and less frequently in internal organs. They are often delineated from surrounding normal hypodermis by fibrous septa. There are numerous subtypes of benign lipomas. At the malignant end of the spectrum is the liposarcoma, which likely arises de novo, rather than from malignant transformation of benign lipomas.2 Specific variants of benign lipomas (e.g., angiolipoma, spindle cell lipoma, lipoblastoma, fibrolipoma, adenolipoma) are largely histopathologic distinctions, as their clinical presentations are often quite similar. For the purposes of surgical management, these lesions will be considered together, with special mention made of any identifying or exceptional features.
Lipomas are the most common soft tissue tumor, occurring in between 0.1% and 1% of the population.3
Lipomas present as soft or rubbery nodules or masses located within the subcutaneous tissue. They are poorly defined and freely mobile, unless trapped beneath skeletal muscle or galea, which limits their lateral mobility. The overlying epidermis appears clinically unremarkable. Lipomas commonly present as slow-growing tumors with a size range of approximately 1 to 10 cm. They are most often confined to the hypodermis but may achieve substantial mass if left intact for many years. Most lipomas are painless and asymptomatic, but anatomic locations with restricted room for expansion (e.g., forehead and scalp), and histologic subtype (e.g., angiolipoma) may predispose the patient to developing pain with these lesions. Common anatomic locations include the back, shoulders, neck, and proximal upper and lower extremities.3,4 Lipomas that occur on the forehead are often buried underneath the frontalis muscle or galea.5
Lipomas most often present as a solitary lesion, but multiple lesions can occur in certain circumstances, such as familial lipomatosis and genodermatoses such as Gardner’s syndrome, Proteus syndrome, neurofibromatosis, Cowden syndrome, Bannayan–Riley–Ruvalcaba syndrome, and others.6
Furthermore, certain lesions can mimic lipomas. In some cases, the alternative diagnosis may not be known or suspected until the tumor is assessed intraoperatively. For example, a liposarcoma may be brighter yellow and greasier than a typical lipoma. A lesion that felt rubbery and was clinically consistent with a lipoma, may have the appearance of a vascular tumor intraoperatively. In such cases, it may be advisable to remove a smaller biopsy sample, terminate the case prematurely, and plan a more definitive approach once the results of histopathology are known. Certain unexpected tumors, such as ...