A Case of Nevus Lipomatosus Superficialis with Features of a Spindle Cell Lipoma Roxanne Rajaii, MS, DO1; Nicky Gazy, BS2; Megan Hakim, PA-C3; Sean Stephenson, DO4 1 Beaumont Health Systems -- Farmington Hills Campus; Farmington Hills, Michigan 2 Western University of Health Sciences – Pomona, California 3 Affiliated Troy Dermatologists -- Troy, Michigan 4 Dermatopathology Laboratory of Central States -- Troy, Michigan ABSTRACT NLS may be differentiated from other entities in the differential diagnosis such as nevus sebaceous, neurofibromas, fibrolipomas, hemangiomas, lymphangiomas by clinical presentation, and definitively Nevus lipomatosus superficialis (NLS) and spindle cell lipoma (SCL) are both relatively rare benign by histology. Histopathology of NLS shows a dermal proliferation of mature adipocytes that may be neoplasms. NLS can be further subdivided into two clinical types: the classical type and the solitary type. connected to the subcutaneous tissue or separated from the subcutis by collagen.2 The adipocytes The classical type typically presents in the lumbosacral area at birth or within the first three decades of life may present solitarily between collagen bundles or form aggregates around blood vessels or eccrine as multiple soft, non-tender papules or nodules, which commonly coalesce to form plaques. The solitary glands. Infrequently, spindle cells representing immature fat cells may be present. Cases of co- form has no location preference and usually occurs later in life as a nodular lesion. A SCL is usually found existing café-au-lait macules, scattered leukoderma, hypertrichosis, and comedo-like lesions within a in the subcutaneous tissues, with rare intradermal cases reported in the literature. This neoplasm most NLS have been reported.3,6 commonly occurs on the neck, shoulders, or back of middle-aged to elderly males as a subcutaneous nodule. In this case report, the authors present a rare and interesting presentation of a NLS with co- A spindle cell lipoma (SCL), and its pleomorphic subtype, in contrast to NLS, most commonly Figures 2 a-c: existing features of a dermal SCL. presents in the fourth to seventh decade of life as a well-circumscribed mass in the subcutaneous Histopathology at 1x (top tissue of the upper back, posterior neck, or shoulders.7 Diagnosis of SCL and the pleomorphic image) and 10x (middle CASE REPORT subtype requires mature fat cells, spindle cells, and strands of strongly eosinophilic collagen.7 and bottom images) A sixty-two-year-old male presented with a chief complaint of an asymptomatic, enlarging growth located Although SCL typically arises in subcutaneous tissue, rare cases of SCL and the pleomorphic magnification. on the left lower extremity that had been present for approximately three years. He denied associated subtype occurring within the dermis have been reported. The dermal SCL and pleomorphic lesions symptoms including pain, tenderness, pruritus, bleeding, ulceration, and discharge. Furthermore, he differ from the classic SCL as they are poorly circumscribed and unencapsulated.4 In addition, the denied any previous evaluation and treatment of the lesion. Patient reported no prior personal or family dermal variant of a SCL may not have a predilection for any specific site or may have a slight history of skin cancer. predilection for the thigh-buttocks-groin area.8 On examination, the patient was a Fitzpatrick skin type II with a solitary 1.5 cm skin-colored to pink Our case highlights a rare and interesting presentation of a NLS with co-existing features of a dermal pedunculated papule on the left proximal posterior thigh as shown in Figure 1. A shave biopsy of the SCL, one of only a few reported in the literature. Neither NLS or SCL have concern for systemic lesion was performed and a differential diagnosis included neurofibroma, benign intradermal nevus, involvement or malignancy. Therefore, treatment is not necessary for any reason other than fibroepithelial polyp, basal cell carcinoma, and amelanotic melanoma. cosmesis, and excision is curative with rare recurrence. Rarely, these lesions may ulcerate with associated foul-smelling discharge. In such instances, surgical excision may be warranted.1,2 Histologic sections demonstrated a pedunculated papule with basket-weave stratum corneum and a CONCLUSION relatively normal appearance to the epidermis. Within the dermis, relatively normal collagen bundles with an increase in fibroblasts within the superficial dermis were observed. Of note, lobular aggregations of In conclusion, nevus lipomatosus superficialis (NLS) is a relatively uncommon hamartomatous neoplasm. A adipocytes were found to be replacing much of the dermis with many areas of the adipocytes showing high index of suspicion, along with histopathological correlation, is needed to diagnose this benign spindle cells and abundant mucin (Figures 2a-c). Based on the histology, a diagnosis of nevus condition. Even more uncommon are features of a spindle cell lipoma, another rare benign tumor, within a lipomatosus superficialis with features of a spindle cell lipoma was made. Due to the benign nature of this NLS. The authors present such a case of a rare solitary-type adult-onset NLS with features of a SCL, one entity, no further treatment was necessary or recommended. Excision was discussed with the patient in of only a few cases documented in the literature to date. case of recurrence of the lesion, if desired. Figure 1: Clinical photograph of REFERENCES lesion prior to 1. Buch AC, Panicker NK, Karve PP. Solitary nevus lipomatosus cutaneous superficialis. J Postgrad Med. 2005;51:47–8. 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