Desmoplastic cutaneous leiomyosarcoma: case report and review of the literature

We report the case of a 51-year-old man with an asymptomatic indurated plaque on the chest wall that was surgically excised and submitted for histopathological examination. Microscopically, the dermis was occupied by a neoplastic process with spindle-shaped cells arranged in longitudinal fascicles with cytologic atypia; the abundant sclerotic stroma was composed of hyaline material. Tumoral cells showed immunohistochemical reactivity to smooth muscle markers. The diagnosis was desmoplastic leiomyosarcoma of the skin. This unusual entity is identified and discussed, and we review the literature.     

Primary leiomyosarcoma of the skin

Leiomyosarcomas of the skin are frequently misdiagnosed clinically. This tumour however, exhibits typical histological and immunohistochemical features. This collection of seven cases of cutaneous leiomyosarcoma on the trunk and limbs of adults with a mean age of 63 years and a range of 49-78 years demonstrates that the clinical diagnosis in each case, from seven different clinicians, did not include the correct diagnosis. In each case, the special immunohistochemical stains were helpful in making the diagnosis with actin and vimentin being positive and S100 and prekeratin stains being negative.     

原发性皮肤平滑肌肉瘤

平滑肌分布广泛,平滑肌肉瘤多发生于深部软组织如子宫、后腹膜、肠系膜及胃肠道等,原发于皮肤的浅表软组织平滑肌肉瘤非常少见,占软组织肉瘤的4.0%～6.5%,约占所有恶性肿瘤的0.04%.根据生物学行为的不同,皮肤平滑肌肉瘤分为真皮型和皮下型,真皮型起源于立毛肌,皮下型起源于血管壁.为提高对这一少见肿瘤的认识,对原发性皮肤平滑肌肉瘤的研究进展作一介绍.     

Granular cell leiomyosarcoma of the skin

A case is presented of a multifocal malignant neoplasm involving the skin of the upper back in a 10-year-old boy following radiation therapy to the head and neck for a cerebellar medulloblastoma. Histologically, the neoplastic cells were remarkable for the presence of abundant periodic acid-Schiff (PAS)-positive diastase-resistant intracytoplasmic eosinophilic granules. Immunoperoxidase procedures revealed strong positive staining of the tumor cells with desmin, vimentin, and smooth muscle myosin antibodies, and negative staining for myoglobin, S-100 protein and keratin, thus supporting a smooth muscle line of differentiation for this neoplasm. Electronmicroscopy demonstrated numerous intracytoplasmic autophagic vacuoles that corresponded to the granules observed under the light microscope. Leiomyosarcoma should be entertained in the differential diagnosis of poorly differentiated cutaneous neoplasms histologically characterized by a proliferation of cells containing abundant granular eosinophilic cytoplasm.     

结缔组织增生性毛发上皮瘤

组织病理特征 本文2张组织病理图片的主要特征是：表皮轻度萎缩,真皮内有较多基底样细胞组成的条索或团块,大小及形态不一,基底样细胞条索周围纤维组织增生：部分团块内可见角囊肿,个别角囊肿周围可见多核巨细胞。[第一段]     

Desmoplastic fibroblastoma

Previous reports of a distinctive, fibrous, soft-tissue tumor include eight patients with subcutaneous lesions and six patients with intramuscular lesions. We report a 48-year-old woman with a 2-cm cutaneous and subcutaneous nodule on the left arm with the same histologic features. An excisional biopsy showed a large, well circumscribed tumor replacing the reticular dermis and subcutaneous tissue. The tumor was relatively hypocellular and composed primarily of large, spindled, plump or stellate fibroblasts haphazardly dissecting between thickened Fibrotic collagen bundles. The stroma contained a large amount of much which was positive with alcian blue at pH 2.5, and relatively numerous mast cells were present. The fibroblastic-like cells were positive with Vimentin and Factor XIIIA and negative with S-100, desmin, actin and keratin.     

Desmoplastic trichoepithelioma

A 20-year-old male presented with a 4 year history of a solitary nodule, 8 mm in diameter on the left temple. It was covered by normal skin, with a central depression and elevated borders. Histopathology showed numerous born cysts amidst nests and strands of basaloid cells surrounded by a dense fibrous stroma. The clinical and histopathological features were characteristic of desmoplastic trichoepithelioma.     

Desmoplastic seborrheic keratosis

Eleven cases of seborrheic keratoses with desmoplastic stroma and associated nests and cords of squamous epithelium simulating infiltrating carcinoma are presented. There were 7 males and 4 females ranging in age from 44 to 88 years (mean = 62). Eight cases were on the head and neck, one each on the lower and upper extremity, and one on the pubic area. Clinical diagnoses included seborrheic keratosis, squamous and basal cell carcinoma, and dermal nevus. Histologically, the lesions were characterized by exophytic growth pattern of basaloid and squamous cells, without cytologic atypia, and well-demarcated peripheral borders, typical for that seen in seborrheic keratoses. Squamous eddy formation with parakeratosis and spongiosis was present in all cases. Located within the body of the lesions were irregular nests and cords of squamous cells extending into the surrounding dermis with associated fibroblastic dermal proliferation trapping the epithelial nests, simulating invasive carcinoma. Immunohistochemically, the epithelial nests were cytokeratin positive and HPV negative, and the dermal stromal cells were vimentin positive and factor XIIIa, cytokeratin, and CD34 negative. Adjacent changes of carcinoma, trichilemmoma, verruca, or other adnexal neoplasm were not identified. Seborrheic keratoses may demonstrate desmoplastic changes analogous to that seen in desmoplastic trichilemmomas. Awareness of these changes in seborrheic keratosis will avoid misdiagnosis and excessive therapy.     

结缔组织增生性恶性黑素瘤

结缔组织增生性恶性黑素瘤是近年来提出的一种较少见的肿瘤.现报告58例,其特点为肿瘤细胞呈梭形,肉瘤样,背景富含胶原.部分病例见到亲神经现象,表皮内可见恶性雀斑样痣或发育不良痣中所见的异型黑素细胞,真皮常见日光照射变化.绝大部分病例S100蛋白强阳性.预后与普通恶性黑素瘤相似,为高度恶性.     

Desmoplastic trichilemmoma.

Seven cases of desmoplastic trichilemmoma (DT), a recently described pseudomalignant variant of trichilemmoma, are reviewed. The tumor generally occurs in men after the fifth decade of life and presents as a small solitary nodule on the face. It is frequently misdiagnosed clinically as a basal cell carcinoma or a papilloma. Histologically DT displays a superficial lobular growth arranged about a central prominent desmoplastic stroma. At the periphery, the tumor lobules show the typical features of trichilemmoma. In contrast, at the center the cells assume a more random pattern of cords and strands traversed by the hyaline stroma, mimicking invasive carcinoma. The tumor's architectural pattern, in particular the perilobular hyaline mantle, enables DT to be differentiated from basal cell carcinoma and malignant trichilemmoma. Immunohistochemical analysis failed to demonstrate human papilloma virus (HPV), epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), and alpha-lactalbumin in tumor epithelium. Keratin was expressed by the central pseudoinvasive epithelial cords. Neither factor XIIIa nor keratin expression was found in the stromal cells, which stained only for vimentin. These findings suggest that DT is not an HPV-induced epithelial proliferation and that the stroma is not the result of degenerative changes in tumor epithelium. Instead, there appears to be a fibroblast-mediated, dendrocyte-independent, stromal reaction producing this appearance.     

Desmoplastic malignant melanoma.

A 68-year-old man sought dermatologic attention for a tumor of the arm. Biopsy specimen showed abnormal, essentially amelanotic, spindle-shaped cells in the cutis, greatly fibrotic stroma, and focal epidermal invasion. Desmoplastic malignant melanoma was diagnosed. The lesion was widely excised and axillary lymphadenectomy performed; one node showed metastasis. Nine months later, he died with widespread metastatic disease. To our knowledge, this is the first report of this entity since its delineation in 1971 and the only case in which diagnosis was established on initial biopsy and followed by definitive therapy. Desmoplastic melanoma has been confused with benign fibrosis, invasive fibromatosis, and fibrosarcoma, and is another example, with morpheaform basal cell carcinoma and sclerodermoid metastatic lesions from breast carcinoma, in which desmoplastic stroma may obscure the epithelial nature of cutaneous neoplasm.     

Cutaneous leiomyosarcoma

Primary cutaneous leiomyosarcomas are rare mesenchymal skin tumors with relatively good prognosis and low risk of metastasis if there is no subcutaneous involvement. A 48-year-old patient with a primary cutaneous leiomyosarcoma of ten years duration is described. Therapy and differential diagnosis are discussed.     

Cutaneous leiomyosarcoma on the trunk

Cutaneous leiomyosarcoma is a relatively uncommon tumor that accounts for 7% of all soft tissue sarcomas. It occurs more frequently in males between 50-70 years and only 10-15% of cases are located on the trunk. Radiotherapy and previous trauma have been implied as risk factors. We report the case of a 57 year-old male with an eight-month history of a hard painless erythematous-violaceous tumor on the presternal region. Histopathology evidenced a malignant spindle cell tumor, "cigar" shaped, with pleomorphic nuclei and a high mitotic index that occupied the entire dermal thickness. Immunohistochemical staining of the tumor cells was positive for smooth muscle actin, desmin and vimentin and negative for S-100 protein and pan-cytokeratin, which supported the diagnosis of dermal leiomyosarcoma. Radical surgery was performed to remove the tumor.     

Cutaneous leiomyosarcoma on the face

Leiomyosarcoma is a rare skin tumor, most common in white men in the fifth to eighth decades of life. Primary tumors are classified in dermal or subcutaneous, that differ by clinical and prognostic features. They may appear on any site of the body, but are rare on the face. A 54-year-old female was admitted with a 5cm exophytic nodular lesion of 8 months duration on the right cheek, site of previous chronic radiodermatitis. Histopathology revealed spindle-shaped cell neoplasia, positive for smooth muscle actin on immunohistochemistry. Cutaneous leiomyosarcomas on the face are rare and may occur in previously irradiated areas. Immunohistochemistry is mandatory for an accurate diagnosis. Its similarity with other tumors may complicate the diagnosis, with delay expansion of the tumor.