Leiomyosarcoma and Pleomorphic Dermal Sarcoma: Guidelines for Diagnosis and Treatment

Pleomorphic dermal sarcoma of the scalp - A single-centre experience

BACKGROUND

Pleomorphic dermal sarcoma (PDS) of the scalp is a rare tumour which is usually slow growing, but occasionally displays rapid growth and has a low rate of local recurrence. Surgical resection is the mainstay of treatment, with or without radiotherapy. The aim of this study is to describe the surgical approach and the additional benefit of radiotherapy to the treatment of these patients.

METHODS

Retrospective, single-centre analysis of patients with PDS of the scalp that underwent surgical resection between 2007 and 2021 (n = 24). Treatment variables including depth of resection (superficial or deep to the galea aponeurotica) and adjuvant radiotherapy were investigated.

RESULTS

Twenty-four patients were included in this study. Median age was 80 (range, 52-95), with a median ASA score of 3 (2-3). Sixteen (66.6 %) patients underwent surgical resection including the galea, while the rest (n = 8) did not or was not known. Radiotherapy was given in 7 (29 %) patients in which only 3 (12.5 %) were in the galeal resection group. Reasons for radiotherapy administration were concomitant SCC found at the same area of resection and close margins. In a median follow-up of was 26.2 months (range, 13.6-102.5) there was only one recurrence event.

CONCLUSIONS

PDS of the scalp can be safely managed with a surgical resection if clear surgical margins are achieved without radiotherapy with good oncological outcomes.

Cutaneous leiomyosarcoma: a retrospective review of 45 cases

Primary cutaneous leiomyosarcoma (LMS) is a rare soft tissue tumour type with two subtypes, dermal and subcutaneous. As deeper tumours confer a worse prognosis, they require a more aggressive approach. Conversely, a more conservative surgical approach for dermal LMS has been suggested. Few studies have comprehensively reported both clinical surgical and histological excision margins. Therefore, we sought to provide margin recommendations based on our experience and review of the existing literature. We undertook a retrospective case-note review (1998-2019) of cutaneous LMS management to establish histological/surgical margins using pathology/electronic patient records. The diagnosis was made and classified by an experienced dermatopathologist according to the World Health Organization classification. In the dermal LMS cohort (n = 35), mean peripheral and deep histological margins were 5.4 mm (range 0.5-20) and 5.6 mm (range 0.1-14.5), respectively. The incomplete excision rate was 31% (11 of 35). There were no recurrences. In the subcutaneous LMS cohort (n = 10), mean peripheral and deep histological margins were 5.7 mm (range 0.2-14) and 1.1 mm (range 0.2-1.7), respectively. The incomplete excision rate was 40% (4 of 10). The recurrence rate was 20% (2 of 10) despite achieving histological clearance after 1 year. One lung metastasis occurred 1 year following an adequately excised primary scalp LMS. Thus, for dermal LMS we propose a clinical margin of 5-10 mm (depending on lesion size) at the initial excision or at scar re-excision following involved/close histological peripheral and/or deep margins (i.e. < 1 mm). For subcutaneous LMS, we suggest a clinical margin of 15-20 mm (depending on lesion size) to achieve a peripheral histological clearance of 10 mm and negative deep margin (i.e. > 1 mm), down to the periosteum/fascia/muscle according to anatomical site. If this is not achieved, a re-excision would be recommended. However, prospective studies are needed for optimal guidance.

Cutaneous sarcoma: a review and practical approach to management

Sarcomas arising in the skin are rare but potentially fatal. These tumours originate from mesenchymal cells and can be divided between those that arise in soft tissue and those arising from bone. General guidelines exist for the management of soft-tissue sarcomas; however, there are no specific guidelines for cutaneous sarcomas. Current literature was reviewed for management of seven cutaneous sarcomas including atypical fibroxanthoma, pleomorphic dermal sarcoma, dermal and subcutaneous leiomyosarcoma, dermatofibroma sarcoma protuberans, Kaposi sarcoma, cutaneous angiosarcoma and malignant peripheral nerve sheath tumour. All suspected sarcomas should be discussed in a sarcoma multidisciplinary team meeting. This article is not a clinical guideline but should serve as a practical summary of how these tumours present, how they are recognized histologically, and how best to manage and follow-up patients. The aim is to support clinicians and facilitate the best and most evidence-based standard of care available.

Prognostic factors for pleomorphic dermal sarcoma: analysis of 1911 cases from the SEER database

Prognostic factors for pleomorphic dermal sarcoma, a rare undifferentiated neoplasm of the skin, are poorly defined, and typical staging systems do not appear to be appropriate for these neoplasms. We; therefore, sought to identify prognostic factors for disease-specific survival and predictors of metastasis.

Pleomorphic dermal sarcomas were identified in the Surveillance, Epidemiology and End Results database (N=1911). Multiple imputation was used to overcome inherent limitations in this dataset to assess prognostic factors using multivariable Cox proportional hazard stratified by (neo)adjuvant radiotherapy and logistic regression for presentation with metastasis.

Age, tumour size and metastasis were independent prognostic factors for cutaneous sarcoma-specific survival. Only tumour size was associated with increased odds of presentation with metastasis, with tumours >4 cm at highest risk. Metastasis is the most important factor in determining outcomes, with age and size as lesser factors. Only tumour size is predictive of metastasis, with larger tumours at highest risk.

Cutaneous leiomyosarcoma: a 20-year retrospective study and review of the literature

Background

Cutaneous leiomyosarcoma is a rare malignant neoplasm with muscular origin, representing 2%-3% of all cutaneous soft tissue sarcomas.

Objectives

The aim of this study was to characterize clinicopathological features of patients diagnosed with cutaneous leiomyosarcoma in our center over the last 20-years.

Methods

A retrospective study of patients with a histopathological diagnosis of leiomyosarcoma between 1999 and 2018 was conducted.

Results

Eleven patients were diagnosed with cutaneous leiomyosarcoma during this period. Most cases occurred in men (n = 7). Age at presentation ranged from 47 to 92 years (mean 64.9 years). Head and neck were the most frequently involved locations (n = 5). Ten leiomyosarcoma were dermal, with one cutaneous metastasis. Immunohistochemical staining was available for 7 patients, demonstrating positivity for smooth muscle actin in all of them. All neoplasms were treated surgically. Mean survival was 32.2-months.

Study limitations

This was a retrospective study based on medical and pathological records.

Conclusions

Histopathology is essential for the diagnosis of leiomyosarcoma, usually revealing a dermal or subcutaneous lesion composed of intertwined fascicles of smooth muscle fibers. Immunohistochemistry is then used to adequately differentiate leiomyosarcoma from other spindle cell tumors. When dealing with cutaneous leiomyosarcoma, it is advisable to carefully evaluate the depth of subcutaneous extension, since even minimal subcutaneous involvement may be associated with a poorer prognosis.

Clear-cell variant of superficial cutaneous leiomyosarcoma associated with RB1 mutation: Clinical, dermoscopic, and histopathological characteristics

Leiomyosarcoma is a relatively rare soft tissue tumor whose clear-cell variant has only been reported in leiomyosarcomas of the uterus. We report here for the first time a primary cutaneous clear-cell leiomyosarcoma in the trunk skin of a 49-year-old man, characterized by a very indolent clinical and dermoscopic presentation, mimicking a dermatofibroma. Genetic analysis of the otherwise healthy patient revealed a germline mutation in the retinoblastoma 1 gene (RB1); the same mutation was found in his son, who had previously developed retinoblastoma. Moreover, the mother of the patient had died of uterine leiomyosarcoma with clear-cell changes. Mutations in the RB1 gene occur commonly in human neoplasms. In this patient, we were able to link his clear-cell variant of cutaneous leiomyosarcoma with the loss of retinoblastoma protein expression, as revealed by immunohistochemical staining analysis.