Diagnosis Of Epithelioid Sarcoma Research Articles

Primary Epithelioid Sarcoma of Frontotemporal Scalp: a Rare Case Report with Recent Literature Review

Epithelioid sarcoma (ES) is a very rare and aggressive mesenchymal sarcoma subtype which represents less than 1% of soft tissue sarcomas (STS). According to the origin of the site, there are two types of ES: distal-type epithelioid sarcoma and proximal-type epithelioid sarcoma. The clinical diagnosis of ES mainly is confirmed by histopathology examination followed by immunohistochemistry. Radical excisional surgery is the best treatment option for epithelioid sarcoma. According to TNM staging, the treatment option will vary from surgery to surgery accompanied with radiotherapy and chemotherapy. Here in, we presented a 36-year-old man had non-healing ulcer in left frontotemporal scalp extending to involve left orbit. Histopathological confirmed epithelioid sarcoma. Magnetic Resonance Imaging (MRI) of Head and Neck revealed that there was mass in left frontotemporal scalp measuring 6.7 X 5.7 X 2.6 cm extending to zygomatic region and left orbit D/D malignant mass/sarcoma with bilateral (B/L) sinusitis. After that patient undergone for Wide Local excision (WLE) surgery on 11th September 2022. Adjuvant Radiation Therapy (RT) 6000 cGy radiation dose in 30 fractions (#) which was 200 cGy per fraction (#) were given during 22nd September to 10th November 2022 due to local advancement of disease. Patient was asked to follow up after 6 weeks after completion of RT. After 6 weeks of surgery, the patient was undergone for MRI and report revealed normal study.

Epithelioid Sarcoma: An overview with emphasis on its differentiation from morphologic mimics

Epithelioid sarcoma (ES) is a malignant mesenchymal neoplasm that exhibits epithelioid cytomorphology and a predominantly epithelial phenotype. The principal types based on histopathological features and location; include the classic or conventional type (CES) and the proximal type (PES). The aim of the study was to analyze our cases of ES regarding clinical, pathological and immunohistochemical features.This is a retrospective study. Seven cases of ES were included in the study. Clinical and pathological details were retrieved from patient records. Details like site, size, histopathological type and IHC features of the tumors were studied. Out of seven, five were PES and two were CES. There were six males and one female; with age ranging from 12 to 68 years. Total five tumors involved extremities. One was noted at a rare site, paratesticular region. Three tumors were larger than 5 cm in greatest dimension. On immunohistochemistry (IHC), all the tumors were reactive for CK, EMA, Vimentin, Ca 125 and showed loss of nuclear expression of INI1. CD 34 was expressed in 6 out of 7 cases.ES is a rare aggressive malignant tumor with dismal prognosis. It is often misdiagnosed because of nonspecific clinical features at presentation. Helpful clues in diagnosis are tumors in young males with epithelioid and/or spindle cell morphology, Rhabdoid cells and granuloma like central necrosis. Co-expression of epithelial and mesenchymal markers along with reactivity for CD34 and Ca 125 and loss on INI1 expression on IHC substantiate the diagnosis of ES.

Epithelioid sarcoma, masquerading as sporotrichosis

Epithelioid sarcoma (ES) is a rare soft tissue neoplasm appearing as multiple slow growing skin nodules. It is a locally invasive tumor, but may metastasize to regional lymph nodes and lungs.
 A 19 year old male presented with multiple painful skin nodules, with linear distribution on right upper limb for 2 years. Initial histology mimicked fungal infection, but response to antifungal treatment was poor. His last skin biopsy showed nodular tumor in the dermis with central necrosis and cytological atypia. Immunohistochemistry confirmed the diagnosis of ES. Since he had radiological evidence of lung metastases, chemo radiotherapy was given. Out of the two phenotypes of ES, distal type may show a sporotrichoid pattern. Histology may mimic non neoplastic granulomatous dermatoses. Cells are positive for cytokeratins, epithelial membrane antigen, vimentin and CD34.
 Diagnosis would be difficult as ES mimics other common non neoplastic granulomatous dermatoses including sporotrichosis.

Primary pulmonary epithelioid sarcoma: a case report

BackgroundEpithelioid sarcoma most frequently occurs in the dermal or subcutaneous area of the distal extremities. To date, there have been three cases of primary pulmonary epithelioid sarcoma reported. We report a case of epithelioid sarcoma that is considered a primary lung tumor.Case presentationA 65-year-old asymptomatic Asian male patient underwent chest radiography during a routine health examination, and an abnormal mass was detected. His past medical history was unremarkable. He smoked 40 cigarettes every day and had slightly obstructive impairment on spirometry. He worked as an employee of a company and had no history of asbestos exposure. He underwent partial resection of the right lung by thoracoscopy. A histological examination of the tumor revealed a cellular nodule of epithelioid and spindle-shaped cells. Some of the tumor cells displayed rhabdoid features and reticular arrangement in a myxomatous stroma. Immunohistochemically, the tumor cells were positive for vimentin, smooth muscle actin (SMA), CD34, and epithelial membrane antigen (EMA); loss of the BAF47/INI1 protein in the tumor cells was also confirmed. A diagnosis of epithelioid sarcoma was established. Careful screening by whole-body positron emission tomography for another primary lesion after surgery did not detect any possible lesion. He had no cutaneous disease.ConclusionTo our knowledge, this is the fourth case of a proximal-type epithelioid sarcoma considered as a primary lung tumor.

Proximal Type - Epithelioid Sarcoma- A Rare And Aggressive Soft Tissue Neoplasm

Abstract Introduction/Objective Epithelioid Sarcoma is a rare malignant soft tissue neoplasm that is well known for local recurrence, regional lymph node involvement, and metastasis. It accounts for less than one percent of all sarcomas. Two subtypes of epithelioid sarcoma are described: the conventional or classic subtype and the proximal subtype, with the classic type being more common than the proximal type. We present a case of proximal epithelioid sarcoma involving the inguinal region, in which the patient presented with the history of weight loss for one year and a slow- growing inguinal mass for the last few months. The biopsy was done in an outside hospital and showed carcinoma of unknown origin. Imaging also failed to reveal any clear source of this mass. Methods The mass was resected and sent to pathology, where H&E staining and immunohistochemistry was done for diagnosis. Results The H&E sections of the left inguinal mass showed proliferation of large epithelioid cells with a moderate amount of cytoplasm, vesicular nuclear chromatin and prominent nucleoli. Mitosis was also seen. Necrosis was not identified. Immunohistochemical staining was done and revealed that the tumor cells were immunoreactive for epithelial marker cytokeratin AE1/AE3 and showed loss of INI-1. Tumor cells were also negative for Myogenin, ERG, HMB-45, MART-1, Myo-D1, S100, and SMA. Considering the cytomorphology and immunophenotypic findings the diagnosis of epithelioid sarcoma, proximal type was made. Conclusion Epithelioid sarcoma is a malignant mesenchymal neoplasm with epithelioid cytomorphology and phenotype. Among the two types of epithelioid sarcoma, the proximal type is reported about 50% less than the classic type and is associated with aggressive behavior and worse prognosis. The classic cytomorphology and immunohistochemistry findings helped us in making the diagnosis in this case.

Effectiveness of Late Line Palliative Chemotherapy by Specialised Approach to Cancer of Unknown Primary: A Case Report

Background: Cancers of unknown primary (CUPs) are defined as histologically confirmed metastatic tumours whose primary site cannot be identified during standard pretreatment evaluation. No specific regimen can be recommended as standard of care. Taxanes and platinum-based regimens are commonly used in the first-line treatment of CUPs, but there is no specific regimen for after second-line treatment. In general, late line chemotherapy is not recommended, but we experienced a rare case of CUPs with disseminated disease that showed improvement with fifth-line palliative chemotherapy by specialised approaches based on the reconsideration of histologic type of cancer. We report a rare case in which palliation was achieved by late line chemotherapy based on pathological review. Case: The case was a 65 year-old man. Transverse colectomy and peritoneal metastasectomy were performed for CUPs. The chemotherapy was continued for 3 years afterwards, and the fourth treatment was not effective. The pathological reexamination was carried out in examining the 5th line treatment, and the chemotherapy (pazopanib) was started under the diagnosis of epithelioid sarcoma. The tumor did not shrink, but the antipyretic effect on tumor fever was achieved, resulting in palliation of symptoms. Conclusions: In general, late line chemotherapy for CUPs is not recommended, but palliative chemotherapy based on pathologic profile may be effective and relieve symptoms of CUPs.

A Rare Epithelioid Sarcoma of the Jaw Mimicking Pleomorphic Rhabdomyosarcoma: Case Report and Literature Review

Abstract Background Epithelioid sarcoma, a rare soft tissue malignancy, is clinically aggressive and commonly affects distal extremities. Proximal, fibroma-like, and angiomatoid variants are lightly outlined. The proximal variant is the most aggressive, composed of larger cells and rhabdoid features, characteristically captivating one’s attention to rhabdomyosarcoma. We present a rare epithelioid sarcoma that histologically mimicked pleomorphic rhabdomyosarcoma of jaw in a 31-year-old male. Objectives To discuss histopathological features of epithelioid sarcoma of rhabdoid features, distinguishing it from other histological mimics like rhabdomyosarcoma. Methods A 31-year-old male was admitted at Muhimbili National Hospital in October 2017 with a 4-month history of slow-growing tender ulcer on the lower right jaw and right-side facial swelling. Clinical impression was squamous cell carcinoma with differential of adenocarcinoma. Various laboratory investigations, imaging, routine staining, and immunohistochemistry were performed. Results CT scan revealed a heterogenous mass in the right submandibular region. Initial examination from incision biopsy showed large oval pleomorphic tumor cells with enlarged vesicular nuclei and abnormal mitoses. Wide excision biopsy followed after conclusion of poorly differentiated carcinoma. Its examination revealed a diffuse, nodular tumor with large, polygonal, round, spindle cells displaying abundant deeply eosinophilic cytoplasm, sometimes showing eccentric vesicular nuclei. Rhabdoid features were observed. Immunohistochemistry revealed strong positivity for wide-spectrum cytokeratin, vimentin, and CD99 and was negative for EMA and myogenin. Conclusion Morphology by routine stains suggested both epithelial and mesenchymal malignancy. Cells with rhabdoid features suggested pleomorphic rhabdomyosarcoma with differential of epithelioid sarcoma. Cytokeratin, vimentin, and CD99 confirmed the diagnosis of epithelioid sarcoma, proximal variant. This case adds information on this rare entity emphasizing application of diagnostic immunohistochemistry procedures in the platform for confirmation of diagnosis to assist in proper patient management.

An Epithelioid Sarcoma of the Right Foot: Raising Awareness of a HighGrade Malignancy

An epithelioid sarcoma (ES) is an infrequent mesenchymal malignancy most commonly encountered in adolescents and young adults in the distal extremities. It has a proclivity for the flexor aspects of the hands and feet with male predilection observed at a ratio of 2:1. The indolent presentation, seemingly unremarkable histopathology, and low incidence of this disease can lead to misdiagnosis. We report a case of a twenty-year old female who presented to her primary care physician with chief complaint of a painful lump beneath her right second and third toes. The tumor was subsequently excised with diagnosis of epithelioid sarcoma.

Epithelioid sarcoma: A case series of three different presentations

Background: Epithelioid sarcoma is a rare malignancy that presents diagnostic difficulties.Cases: We report three cases of epithelioid sarcoma with different presentations and clinical course. One patient had a classicaltype epithelioid sarcoma while rest two suffered from the rarer proximal-type. All three underwent surgical excision while two of them also had postoperative adjuvant therapy. The diagnostic challenges and the final outcome has been discussed in detail.Conclusion: The diagnosis of epithelioid sarcoma needs a high index of clinical suspicion and immunohistochemistry is extremely valuable. Adequacy of index surgery affects the ultimate prognosis.

A Case of Distal Epithelioid Sarcoma of the Thumb Expressing Podoplanin, TLE1 and Ca 125

Distal epithelioid sarcoma is a rare and slowly growing tumor that usually develops in the upper extremities of young adults. Neoplastic cells have both spindle and epithelioid appearance and are characterized by the loss of the nuclear protein SMARCB1/INI1. We present the case of a distal epithelioid sarcoma arising in the thumb of a 14-year-old girl, which immunohistochemically was characterized by the loss of SMARCB1/INI1 protein as well as the expression of podoplanin (D2-40), TLE1, Glut1, and Ca 125; plus, we highlight the differential diagnosis of epithelioid sarcoma from its histological mimics.

Epitheloidzelliges Sarkom der rechten Hand

A 35-year-old man presented with swelling, indurations and nodules on the thumb, wrist and fingers of the right hand. History revealed that the findings were slowly progressive and had been present for at least eight years. Histopathologic analysis of a nodule showed a diffuse infiltrate with atypical spindle-shaped cells and expression of cytokeratin, epithelial membrane antigen (EMA) and CD34; the diagnosis of epithelioid sarcoma (ES) was made. Because of diffuse extension of the tumor, forearm amputation was performed along with axillary dissection and local radiotherapy because of axillary lymph node metastases. ES is a rare subtype of soft tissue sarcoma with a harmless appearance and indolent course over years. ES represents a diagnostic challenge, with consequent delay in diagnosis and adequate treatment. The most important measure in the treatment of ES is early surgical excision with adjuvant radiotherapy if local metastases are present.

Epithelioid Sarcoma of the Parotid Gland of a Child

Epithelioid sarcoma is a rare soft-tissue tumor that usually occurs in young adults, with a median age of 26 years. This malignancy has been divided into distal and proximal types. The latter is found in proximal body sites including the head and neck region. We present a rare case of parotid proximal-type epithelioid sarcoma in a 1-year-old male child; this is the 4th reported case in the literature and the youngest in a pediatric patient to date. The tumor showed prominent rhabdoid features by light microscopy. Immunohistochemical studies revealed positive staining to cytokeratin (AE1/AE3), epithelial membrane antigen, vimentin, and BAF47. Thus, while the tumor resembled a malignant rhabdoid tumor, the positive staining for BAF47 supported instead a diagnosis of epithelioid sarcoma, according to our current understanding of these 2 tumor types. Also, the clinical course was not the typical aggressive behavior of a rhabdoid tumor. The patient underwent radical parotidectomy without adjuvant therapy and remained disease-free at follow-up, 14 months after surgery.

Is preoperative cytologic diagnosis of epithelioid sarcoma possible?

Epithelioid sarcoma (ES) is a rare malignant neoplasm of the soft tissues with a predilection for distal extremities of young adults. A "proximal" variant was recently described. The preoperative fine-needle aspiration cytology (FNAC) differential diagnosis with necrotizing granuloma, carcinoma, melanoma, and other neoplasms with epithelioid morphology can be difficult and few cases have been described in the literature. The authors present the preoperative FNAC findings of 10 aspirates of ES, corresponding to seven patients (four men and three women, ages 13-72 years). The cytologic features were compared with histologic features as well as with the FNA patterns of other neoplasms with epithelioid morphology that may be included in the differential diagnosis. Cytologic smears showed tumor cells with an epithelioid to spindle cell morphology, dispersed and in loose clusters in close relation with a fibrillar hyaline material. The cells showed moderate anisocariosis, a vast well-defined, often dense cytoplasm with immunoexpression of vimentin, cytokeratin, and CD 34. When the FNA cytologic features described above are accompanied by the adequate clinical setting and are supported by immunocytochemistry, an accurate preoperative cytologic diagnosis of ES is possible.

Epithelioid sarcoma with muscle metastasis detected by positron emission tomography

BackgroundEpithelioid sarcoma is an uncommon high-grade sarcoma, mostly involving the extremities.Case presentationA 33-year-old man was referred to our institute with a diagnosis of Volkmann's contracture with the symptom of flexion contracture of the fingers associated with swelling in his left forearm. Magnetic resonance imaging (MRI) showed abnormal signal intensity, comprising iso-signal intensity on T1- and high-signal intensity on T2-weighted images surrounding the flexor tendons in the forearm. Diagnosis of epithelioid sarcoma was made by open biopsy, and amputation at the upper arm was then undertaken. [18F]-2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) detected multiple lesions with an increased uptake in the right neck, the bilateral upper arms and the right thigh, as well as in the left axillary lymph nodes, with maximum standardized uptake value (SUVmax) ranging from 2.0 to 5.5 g/ml. Magnetic resonance imaging confirmed that there was a lesion within the right thigh muscle which was suggestive of metastasis, even though the lesion was occult clinically.ConclusionIncreased uptake on FDG-PET might be representative of epithelioid sarcoma, and for this reason FDG-PET may be useful for detecting metastasis. Muscle metastasis is not well documented in epithelioid sarcoma. Accordingly, the frequency of muscle metastasis, including occult metastasis, needs to be further analyzed.

Epithelioid sarcoma with angiomatoid features: report of an unusual case arising in an elderly patient within a burn scar

Epithelioid sarcoma (ES) is a rare, aggressive soft tissue tumor with a characteristic predilection for adolescents and young adults, and a tendency to occur on distal extremities. We report a case of ES arising in an 80-year-old woman within a burn scar that histopathologically showed unusual 'angiomatoid' features. The patient presented initially with a solitary nodule on her right wrist arising at the site of a burn scar. Histopathologically, the tumor was composed of a proliferation of relatively bland, epithelioid and spindle cells focally arranged in a nodular pattern around areas of 'geographic' necrosis. In addition, there were prominent foci of hemorrhage and blood-filled spaces as well as tumor cells with intracytoplasmic vacuoles, features suggestive of an angiomatous process. Immunohistochemistry showed positivity of tumor cells for cytokeratins and epithelial membrane antigen (EMA) whereas all vascular markers tested were negative. The overall histopathologic features were consistent with a diagnosis of ES. Follow up showed multiple recurrences arising proximally along the right upper extremity. Our case underlines the clinical and histopathological heterogeneity of ES, emphasizing the unusual occurrence of ES with 'angiomatoid' features in the elderly. In this uncommon setting, this tumor should be especially distinguished from epithelioid hemangioendothelioma and epithelioid angiosarcoma. The significance of development of ES on a healed burn scar is uncertain, but may suggest a possible causal relationship.

Rare and aggressive metastatic, axial multifocal local epithelioid sarcoma associated with paraneoplastic granulocytosis and hypoglycaemia

Epithelioid sarcoma is a rare soft-tissue sarcoma (STS; <1% of total STS) that aff ects young, usually male, adults or adolescents. In most cases, the sarcoma grows slowly (over a period of years), involves the dermis, subcutis, or deeper soft tissues in the distal extremities in 55–60% of cases. Epithelioid sarcoma is characterised by diagnostic diffi culties, both clinically and histopathologically, which results in a high frequency of initial misdiagnosis and loss of crucial treatment time. Surgical excision (amputation or wide en-bloc excision), then high-dose radiotherapy represents optimum treatment, however, this regimen is associated with a recurrence rate of 77% and a median overall survival of about 88 months for patients without distant metastases, and just 8 months for those with distant metastases. Unlike in most sarcomas, metastases aff ecting the lymph nodes are common in epithelioid sarcoma. However, the lungs are the most common site of distant metastases in epithelioid sarcoma. Furthermore, multifocal local disease, initial proximal limb or axial tumour location, regional metastases, high mitotic fi gures, necrosis, and haemorrhage or vascular invasion have a more aggressive course, and predict for a poor survival that is free from distant metastasis. Immunohistochemically, most epithelioid sarcoma express vimentin, keratin, epithelial membrane antigen (EMA), CD34 (60%), cyclin D1 and tissue polypeptide antigen (TPA). Coexpression of vimentin and keratin is thought to be characteristic of epithelioid sarcoma. A 37-year-old man was admitted to our hospital diagnosed with epithelioid sarcoma. On admission, the patient had four cutaneous lesions measuring 3–6 cm and a painful right knee. The lesions were localised at the epigastrium, right lateral abdominal area, anterior iliac crest level, spinal region at the level of L3–L5, and right buttock. According to the patient’s recent medical history, the fi rst lesion of around 1 cm seemed to develop on a surgical scar 3 months after a gastric ulcer operation. The lesion was misdiagnosed as infl ammation and was treated with antibiotics. 1 month later, a second lesion developed on his right buttock, and a biopsy by surgical excision yielded a diagnosis of epithelioid sarcoma. Microscopic examination shows nodular growth with central necrosis and haemorrhage (fi gure 1A). Immunohistochemistry showed expression of vimentin (fi gure 1B) and actin. EMA, keratin, CEA, S100p, CD30, CD31, and CD34 were negative. CT scans of the thorax and abdomen, and a bone scan found splenomegaly, multiple lung nodules, enlarged mediastinal, mesenteric, and paraortic lymph nodes, and bone metastases at L3, L5 vertebrae and at the right upper tibia (fi gure 2). Blood analyses showed leucocytosis (white blood cell [WBC] count: 23·9 × 10 cells/L; with neutrophils: 87·9%). Multiple cultures of blood, urine, sputum, and dermal lesions found no evidence of infection during the patient’s clinical course. Based on prominent leucocytosis, we measured serum granulocyte colony-stimulating factor (G-CSF). The highly increased serum G-CSF of more than 2 μg/L (normal <40 ng/L) suggested that a G-CSF-producing epithelioid sarcoma was the cause of leucocytosis. The Lancet Oncol 2006; 7: 82–84

Epithelioid sarcoma presenting as pulmonary cysts with cancer antigen 125 expression

A 39-year-old Japanese woman presented with a swollen right hand and a right-sided pneumothorax. Chest CT revealed bilateral multiple pulmonary thin-walled cysts measuring<or=1 cm in diameter and small nodules. An initial skin biopsy led to a misdiagnosis of metastatic adenocarcinoma, as tumour cells were positive for cytokeratin, epithelial membrane antigen, carcinoembryonic antigen and cancer antigen 125. However, chemotherapy proved ineffective, and the skin biopsy was repeated. A final diagnosis of epithelioid sarcoma (ES) was made. Open lung biopsy showed that the pulmonary nodules represented metastases of ES. Although the pulmonary cyst walls did not contain tumour cells, bronchiolar wall adjacent to the cysts had been infiltrated by tumour cells. These findings suggested that pulmonary cysts, a rare form of pulmonary metastases from soft tissue sarcomas, had developed through a ball-valve effect of metastatic tumour in small airways. However, presence of cancer antigen 125 hindered obtaining a correct diagnosis of ES.

Epithelioid sarcoma metastasis to the gingivae: a case report

We present a rare case of oral metastatic epithelioid sarcoma rapidly growing over the mandibular gingivae; the primary lesion occurred on the wrist and was treated 18 months earlier by surgery and radiotherapy. The oral metastatic lesion was resected and controlled by chemotherapy. This case has been followed for 2 years with good control of the resected oral metastatic lesion. Histologically, round to oval-shaped tumour cells with abundant eosinophylic globular cytoplasm and eccentrically localized nuclei, lack of epithelial features by electron microscopic study, and the immunohistochemical and cytologic features of tumour cells led into the diagnosis of epithelioid sarcoma. To our knowledge, no reports have been published of its occurrence in the oral cavity

Epithelioid sarcoma of the extremities: a dismal long-term outcome

AbstractEpithelioid sarcoma is a rare histologic subtype of sarcoma. The clinical behavior and prognostic factors nfluencing survival in this disease are examined. A review of clinicopathologic features of patients with epithelioid sarcoma prospectively followed between September 1981 and April 2001 at the Cancer Institute Hospital was performed.Eight patients (4 men and 4 women) constituted the subjects of this study, with a mean age of 41 years. Tumors presented in the lower extremity in 62.5% of patients and in the upper extremity in 37.5%. All patients were followed for at least 10 years from the time of diagnosis or until death. The follow-up ranged from 17 to 228 months, with a mean of 78 months. At least one local recurrence was seen in 50% of patients. During the course of the disease, metastases to regional lymph nodes developed in 50% of patients and metastases to the lungs in 62.5%. The median survival was 31 months, with a 25% 5-year and 10-year survival rate. Pulmonary metastases were correlated with decreased survival. A delay in diagnosis of epithelioid sarcoma is common. Epithelioid sarcoma differs from other sarcoma subtypes in its propensity for nodal spread and local recurrence. Chemotherapy and radiotherapy have an insignificant effect on the course of epithelioid sarcoma. Careful follow-up, evaluating local recurrence, nodal spread, and pulmonary metastases, is warranted. The long-term outcome of epithelioid sarcoma is dismal.

Epithelioid Sarcoma of the Penis: Clinicopathologic Study of a Tumor with Myogenic Features and Review of the Literature Concerning this Unusual Location

Soft tissue tumors of the penis are uncommon. We report here the clinicopathologic features of a penile epithelioid sarcoma (ES), review the literature concerning this unusual location and focalize our attention on its differentiation. The 34-year-old patient was admitted for abrupt urinary retention due to the growth of a firm and painful plaque on the left side of the shaft, three years previously clinically diagnosed as Peyronie's disease. Magnetic nuclear resonance revealed an infiltrating lesion of both corpora cavernosa. Histology of bioptic fragments showed a nodular malignant spindle and epithelioid cell tumor with focal necrosis and relatively high mitotic rate. Based on the immunohistochemical data (cytokeratin+, vimentin+, EMA+, CD34+, and S100-), the diagnosis of ES was strongly considered. Penectomy was undertaken and the diagnosis confirmed by both light and ultrastructural microscopy. The 22 month follow-up was free of recurrences and metastases. Although not dissimilar from the 10 previously described ES of the penis in terms of natural history and histology, the tumor reported here showed myogenic features as revealed by both immunohistochemistry (immunoreactivity for muscle specific actin) and ultrastructure (intercellular junctions, discontinuous basal lamina, pinocytotic vesicles and thin filaments with intercalated dense bodies). Although previously observed in ES of other sites, this feature has never been established in ES of the penis.