A 50-year-old man comes to the office for evaluation of a mass on his back. He has had the mass for several years, and it has increased only slightly in size during that time. The patient has 2 other similar lesions, one on his arm and the other on his leg. The lesions are painless, and he has no other symptoms. Vitals signs are normal. Examination shows multiple subcutaneous, soft, freely mobile, and nontender masses. The lesion on his back is shown in the image. Histologic examination of the mass is most likely to show which of the following findings?

Question

A 50-year-old man comes to the office for evaluation of a mass on his back.  He has had the mass for several years, and it has increased only slightly in size during that time.  The patient has 2 other similar lesions, one on his arm and the other on his leg.  The lesions are painless, and he has no other symptoms.  Vitals signs are normal.  Examination shows multiple subcutaneous, soft, freely mobile, and nontender masses.  The lesion on his back is shown in the image.  Histologic examination of the mass is most likely to show which of the following findings?

Quizplus · Accepted Answer

This patient has a soft, mobile, subcutaneous mass consistent with a lipoma. Lipomas are very common, benign tumors that arise from the subcutaneous fat. They typically occur in middle-aged adults and are generally stable or enlarge slowly over time. The overlying epidermis is normal. The diagnosis of lipoma is usually easy to make on clinical examination. However, if necessary, excisional biopsy can be performed and shows well-differentiated, mature adipocytes with an intact fibrous capsule. Because lipomas are generally harmless, most can be left in place, although excision can be considered for cosmetic reasons or patient discomfort. (Choice B) Osteosarcoma is usually seen in children and young adults; it is uncommon in older adults, in which it is often associated with Paget disease of bone. It presents with local pain and swelling; the mass, if palpable, is nonmobile. Histopathology shows pleomorphic malignant cells with hyperchromatic nuclei forming neoplastic osteoid or bone. (Choice C) Erythema nodosum presents acutely as tender, subcutaneous nodules in the lower extremities. It occurs in association with a variety of infectious (eg, herpes simplex) and inflammatory (eg, sarcoidosis) conditions. Histopathology shows inflammation in the subcutaneous fat (panniculitis) with edema, fibrinous exudate, and a variable cellular infiltrate (neutrophils, lymphocytes, histiocytes). (Choice D) Cutaneous squamous cell carcinoma typically forms an enlarging epidermal nodule in sun-exposed areas. The lesions often develop a thickened, rough surface or ulcerate with crusting and bleeding. Pathologic findings include sheets of eosinophilic squamous cells with keratin pearls and intercellular bridges. (Choice E) Cutaneous neurofibromas usually manifest during early adolescence as raised, fleshy tumors (<2 cm) that often increase in size and number with age. They are composed primarily of Schwann cells (spindle-shaped cells with wavy or serpentine nuclei), fibroblasts, and perineural cells. Educational objective: Lipomas are common, benign tumors that arise from the subcutaneous fat and present as soft, mobile masses that are stable or enlarge slowly over time. The diagnosis is usually made clinically, but histopathology shows well-differentiated, mature adipocytes with a fibrous capsule. __________ References: Lipomas, pathology. (http://www.ncbi.nlm.nih.gov/pubmed/29493968)

A 50-Year-Old Man Comes to the Office for Evaluation of a Mass