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Abstract
Nevus lipomatosus cutaneous superficialis (NLCS) is a rare cutaneous hamartomatous lesion, histopathologically characterized by the presence of ectopic dermal adipocytes. Herein, reported is the clinicopathological aspect of six cases of NLCS, consisting of three males and three females, with age at presentation ranging from 18 to 47 years and duration of lesion ranging from 2 to 18 years. Out of the six cases, five were of solitary NLCS, who presented with nodules or polypoidal masses of variable sizes and duration. The lone case of classical NLCS presented with multiple skin-coloured cerebriform nodules over the right lower back in zosteriform distribution. The commonest location was lower back and thigh. Histopathological examination revealed lobules of mature adipocytes in the papillary and/or reticular dermis in all cases, thereby establishing the diagnosis of NLCS. Additional microscopic features encountered were surface ulceration, focal myxoid degeneration, mild perivascular lymphocytic infiltrate and attenuation of adnexal structures.
Keywords: Adipocytes, classical type, dermis, ectopic, hamatomatous, nevus lipomatosus cutaneous superficialis, solitary type
Introduction 
Nevus lipomatosus cutaneous superficialis (NLCS) is a rare benign hamartomatous skin lesion characterized by the presence of ectopic mature adipose tissue in the dermis.[1] It was first reported by Hoffmann and Zurhelle, way back in 1921.[2] Even after hundred years, the literature on NLCS is sparse, limited to individual case reports and small case series. We, herein, present the clinicopathological aspect of six NLCS cases diagnosed over twenty months. This case series would serve as a useful addition to the existing literature on NLCS.
Case Report (s) This is a retrospective case series of six biopsy-proven cases of NLCS encountered between June 2018 and January 2020. Detailed clinical information, treatment plan and follow-up data were retrieved from the medical case records [Table 1]. These patients presented to the surgical or dermatological outpatients' department of Andaman and Nicobar Islands institute of medical sciences, Port Blair, with the complaint of slow-growing, non-painful lesions. A 30-year-old male (Case 2), a case of solitary NLCS over left gluteal region, presented with ulceration over the lesion [Figure 1]a. An 18-year-old female [Case 3, classical NLCS] presented with multiple cerebriform nodules, which were skin-coloured with yellowish hue and were spread over an area of 30 × 12 cm on right lower back in zosteriform distribution, since birth [Figure 1]b. The other four cases were of solitary NLCS, who presented with nodules or polypoidal masses of varying duration and sizes. There was no history of local trauma or any significant past medical or family history in any of the six cases. Their complete hemogram, blood biochemistry, coagulation parameters and urine analysis were within normal limits. However, lipid profiling was not done. All the six patients underwent complete surgical excision of the lesion under local anesthesia. In Case 3, owing to the large size of the lesion, electrosection was performed in multiple sittings. Suturing of the defect was done if the post-dissection defect was larger [Figure 1]c. The archived haematoxylin and eosin (H&E) stained slides of all cases were reviewed independently by two pathologists. Microscopically, the features were typical of NLCS [Figure 1]d and [Figure 1]e. The histopathologic findings are documented in [Table 1]. None had recurrence at the end of six-month follow-up.
Figure 1: (a to f) [original]: (a) Case of solitary NLCS (Case 2) showing a focally ulcerated polypoidal lesion over left gluteal region; (b) Case of classical NLCS (Case 3) depicting multiple, grouped, cerebriform nodules over right lower back; c) Clinical picture of Case 3 after three-fourth of the lesion being excised by staged electrosurgery. Area marked by red circles represent healed scars following electrosection in previous sittings. The area marked with green rectangle represents electrosection of a portion of NLCS with suturing of the defect. Inset shows the gross appearance of excised specimen with homogenous yellowish areas below the epidermal surface; d) Microscopy of Case 3 showing irregular acanthosis, increased capillaries in the papillary dermis and lobules of adipocytes in the reticular dermis (H&E, 40x); e) Microscopy of Case 4 displaying largely unremarkable epidermis, increased dermal vasculature, haphazardly arranged collagen bundles and adipocytic tissue in the mid and lower dermis (H&E, 40x); f) Microscopy of Case 5 showing focal subepidermal myxoid degeneration and perivascular lymphocytic infiltrate (H&E, 100x) while inset highlights the scattered stellate-shaped fibroblasts and mast cells in the myxoid area (H&E, 400x) Discussion NLCS, based on the clinical presentation, is classified into the classical Hoffmann-Zurhelle form and the solitary form. The classical form occurs at birth or during early life and manifests as groups of multiple, cerebriform, papules or nodules, with zonal/segmental distribution that often coalesce to form a plaque. On the contrary, the solitary form, as the nomenclature suggests, presents as a single nodule, usually after third decade of life.[1],[3] Our observation is similar to that of Dudani et al.[4] and Alotaibi et al.[5]who noted a predominance of the solitary form whereas, Goucha et al.[6]and Kumaran et al.[7] found classical form as the commoner NLCS type in their study. Interestingly, Kumaran and colleagues[7] reported a case of classical NLCS who later on developed solitary lesions as well. A comparison of the present case study with other case series is presented in [Table 2] and it is clearly evident that NLCS has no gender predilection, presents as slow-growing mass/masses of variable size and duration and commonly involves lower back, gluteal region and lower limbs.[2],[4],[5],[6],[7] Of note, we and Dudani et al.[4] came across a handful of cases in a much shorter time span in contrast to other investigators. Hence it is unclear, whether NLCS has truly low prevalence in the population or is an underdiagnosed entity.
Table 2: Comparative analysis of published Nevus Lipomatosus Cutaneous Superficialis (NLCS) case series with the present studyAs highlighted in the present study and others, NLCS, especially the solitary form, can clinically mimic papilloma or acrochordon and is usually misdiagnosed clinically. Histopathological examination forms the corner stone for the final diagnosis of NLCS and the defining microscopic feature is the presence of adipose tissue in papillary and/or reticular dermis. The overlying epidermis may display hyperkeratosis, acanthosis, papillomatosis and focal elongation of rete ridges. The adnexal structures may be unremarkable or attenuated. In our study cohort, all the cases had reduction in adnexal structures and there were dilated small-caliber blood vessels within the lobules of adipocytes. Two cases demonstrated focal areas of myxoid degeneration [Figure 1]f. NLCS needs to be histologically differentiated from focal dermal hypoplasia or Goltz syndrome, which is characterized by attenuation of dermal collagen and its subsequent replacement by adipose tissue.[4] Lipofibroma, which usually presents as pedunculated mass, is another close histological differential and shows peri-adnexal adipose tissue admixed with dense stromal collagen.[8] Rarely, spindle cells, representing immature fat cells, may form a substantial portion of the lesional adipocytic population in NLCS and it should be distinguished from other dermal based spindle cell lesions such as neurofibroma, leiomyoma, dermatofibroma.[3]
NLCS has also been found in association with several distinct appendageal tumour or tumour-like entities such as folliculosebaceous cystic hamartomas, nevus sebaceous of Jadassohn, fibrofolliculoma, trichofolliculoma, cylindroma and dermoid cysts.[1],[6],[9],[10] There is no conclusive evidence as to whether these lesions are etiopathogenetically linked to NLCS or are mere incidental findings. The precise histogenesis of NLCS is still largely unclear. Various hypotheses include origin of adipocytes from pericytes of dermal blood vessels, metaplasia of dermal connective tissue to adipose tissue and developmental displacement of adipose tissue during embryonic life.[6]
Majority of the cases are treated with surgical excision. Intralesional phosphatidylcholine and sodium deoxycholate injection, cryotherapy and carbon dioxide laser therapy are alternative treatment modalities.[2],[11] Although extremely rare, recurrences can occur. Jones et al.[2]reported a case of recurrence after five years post-surgery.
Conclusion NLCS is a rare skin hamartomatous lesion with variable clinical presentation, liable to be misdiagnosed clinically. Unusual presentations and rare associations with other disorders should be kept in mind. Histopathological examination forms the cornerstone for diagnosis. Currently, large multi-centered, detailed clinicopathological studies of NLCS are lacking and the same needs to be encouraged for establishing its true prevalence rate, etiopathogenesis, role of genetic aberrations (if any), clinico-etiopathological differences between classic and solitary form, histopathological markers of disease progression, alternative treatment modalities and prognostication.
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The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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