"Proximal-type" epithelioid sarcoma, a distinctive aggressive neoplasm showing rhabdoid features. Clinicopathologic, immunohistochemical, and ultrastructural study of a series

Vulvar "proximal-type" epithelioid sarcoma: report of a case and review of the literature

Background

The “proximal-type” epithelioid sarcoma is a very rare kind of mesenchimal tumor characterized by the difficulty in histological diagnosis and the very aggressive biological behavior.

Case

We report of a case of a 63 years old woman with a vulvar “proximal-type” epithelioid sarcoma that underwent a radical surgical staging followed by an adjuvant radiotherapy. She is on follow-up care for 14 months and there is no clinical evidence of disease.

Conclusion

Even if quite rare the proximal type epithelioid sarcoma should be regarded as a separate entity of particularly aggressive biologic behaviour. Its diagnosis attracts controversies and criticism related to the surgical approach and the choice of an adjuvant therapy.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1508554852942125

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.

Treatment and outcomes of epithelioid sarcoma of the spine

Epithelioid sarcoma (ES) is a rare soft-tissue neoplasm which is most commonly found in the extremities of young adult males. ES has a poor prognosis due to its aggressiveness as it frequently recurs locally and can undergo lymphatic metastasis to soft tissue, fascia, bone, lymph nodes, lung, and brain. The most common form is the classic-type (granuloma-like), though a more aggressive subtype known as the proximal- or axial-type has also been described. As ES of the spine is exceedingly rare, with only seven patients being reported in the literature, the outcomes of these patients is unclear. We have reviewed the literature of all existing spinal ES cases to recommend treatment strategies and report the first case of proximal-type ES in the cervical spine. Patients with spinal ES had an average age of 20.7 years, with 71.4% of cases being in males. Metastasis was common and was found in 83.3% of patients, with lung metastasis being found in 60% of these patients. Due to the high rates of local recurrence and distant metastasis, the goal of surgery remains gross total resection of all tumor and involved bony elements if feasible without significant neurological deficits. Ligation of involved nerve roots may be necessary to achieve adequate resection of the tumor mass as nerve sheaths can serve as a pathway for extension. In the cervical spine, resection of these lesions is difficult due to involvement of the vertebral arteries in addition to nerve roots, increasing the surgical risk.

Epithelioid sarcoma is associated with a high percentage of SMARCB1 deletions

SMARCB1 gene alterations were first described in highly malignant rhabdoid tumors of the kidney, brain (atypical teratoid/rhabdoid tumor) and soft tissue. An increasing number of tumors have now shown loss of SMARCB1 protein expression by immunohistochemistry, including the majority of epithelioid sarcomas. However, investigations of SMARCB1 gene alterations in epithelioid sarcoma have produced conflicting results. The aim of this study was to evaluate SMARCB1 status using Sanger sequencing of the coding region and multiplex ligation-dependent probe amplification, a rapid and sensitive method for detecting intragenic deletions and duplications, which has not been used in previous studies. Twenty-one epithelioid sarcomas of both classical and proximal type were selected for SMARCB1 gene testing and SMARCB1 immunohistochemistry. Nineteen of 21 (90%) epithelioid sarcomas were SMARCB1 negative by immunohistochemistry. Twelve of the 19 (63%) had adequate DNA recovery for evaluation. Ten of 12 (83%) tumors showed homozygous deletions of the gene. Two cases showed heterozygous deletions and polymorphisms, but no sequence mutations. These results confirm the high frequency of SMARCB1 deletions in epithelioid sarcoma and show that multiplex ligation-dependent probe amplification is a reliable method for detection of deletions in these cases, which can be performed on formalin-fixed, paraffin-embedded tissue. Given the high percentage of SMARCB1 alterations in epithelioid sarcoma, these findings argue against using SMARCB1 gene deletion as a tool in distinguishing them from malignant rhabdoid tumors.

Proximal-type Epithelioid Sarcoma of the Head and Neck (HN): A Study with Immunohistochemical and Molecular Analysis of SMARCB1

Proximal-type epithelioid sarcoma is an aggressive variant of epithelioid sarcoma most often occurring in soft tissues of the proximal limbs, characterized by polygonal cells, marked nuclear atypia, and varied rhabdoid features. Malignant rhabdoid tumor is an aggressive, well characterized entity typically with rhabdoid morphology and involving the kidney of pediatric patients. Rarely, tumors with morphologic and biologic features identical to those in kidney occur in extra-renal sites and are regarded as an extrarenal presentation of the same entity in kidney, named malignant extra-renal rhabdoid tumor. Morphologic and immunophenotypical similarities between proximal-type epithelioid sarcoma and malignant rhabdoid tumor pose a diagnostic challenge and may suggest a relationship between the two. Both tumors are characterized by loss of SMARCB1 (INI1/BAF47/SNF5) expression; however, the molecular events involved differ. Here we describe the immunohistochemical and molecular analysis of three head and neck tumors with morphologic features shared by proximal-type epithelioid sarcoma and malignant rhabdoid tumor. All tumors showed loss of SMARCB1expression. Direct sequencing of the promoter and nine coding exons of SMARCB1, multiplex ligation-dependent probe amplification, and whole genome single nucleotide polymorphism array were performed on the two adult cases and showed only a heterozygous deletion of chromosome 22 in a minority of cells in one of the cases. Though rare, proximal-type epithelioid sarcoma could occur in the head and neck and should be differentiated from other epithelioid tumors by the loss of SMARCB1 expression. The lack of detectable genetic alteration in the SMARCB1 locus in head and neck proximal-type epithelioid sarcoma warrants further investigation into the molecular mechanism underlying loss of SMARCB1 expression.

Proximal-type epithelioid sarcoma of the scrotum: 18F-FDG PET/CT imaging

Proximal-type epithelioid sarcoma is an uncommon but aggressive soft-tissue malignancy involving proximal body parts especially perineum and genitalia of adult patients. This entity is a variant form of the conventional epithelioid sarcoma, which is frequently encountered at extremities of adolescents or young adults. The authors present a case of proximal-type epithelioid sarcoma of the scrotum with comprehensive staging and monitoring with PET/CT.

Cutaneous soft tissue tumors that make you say, "oh $*&%!"

Subsets of cutaneous soft tissue tumors present morphologic features which are diagnostically challenging in part because of their ability to obscure the ultimate nature of the underlying neoplastic process. This review discusses entities, which in the authors' experience, present such challenges. The clinical, histologic, immunohistochemical, and where appropriate, molecular features of these entities are discussed along with their prognosis and differential diagnosis.

A case of the large retroperitoneal solitary fibrous tumor

A rare autopsy case of the extremely large retroperitoneal solitary fibrous tumor is reported. A 52-year-old female with a huge abdominal distention was found dead at home. She showed remarkable emaciation. The autopsy revealed a huge retroperitoneal tumor weighing 11.9kg (36×30×20cm in size), which occupied the entire intraperitoneal cavity. Histologically, the tumor consisted of spindle parenchymal cells with fibrous tissues. Immunohistochemically, CD34 was positively stained, whereas S-100, smooth muscle actin, and factor VIII were negative. Her cause of death was diagnosed as emaciation due to the compression of the entire intestine by the tumor. This is a rare case of the extremely large retroperitoneal solitary fibrous tumor, which caused the occasional intestinal obstruction. This disease should be considered in the differential diagnosis of retroperitoneal large tumors that cause accidental deaths in forensic autopsies.

Soft tissue tumors of uncertain origin

Many soft tissue tumors of childhood lack obvious differentiation toward a defined mesenchymal tissue type or have a phenotype that does not correspond to any defined normal tissue. These challenging tumors are currently regarded as neoplasms of uncertain differentiation. Nonetheless, there have been great strides in the understanding of their pathologic and genetic features and biologic underpinnings. The application of new genetic information to the pathologic diagnosis among this group of tumors is an emerging area in diagnostic pediatric pathology. This article reviews the clinicopathologic features of tumors of uncertain and/or miscellaneous origin, with an emphasis on the unique aspects of these neoplasms in children and adolescents, use of diagnostic adjuncts, and differential diagnosis.

Epithelioid sarcoma of the penis: a case report

INTRODUCTION

Epithelioid sarcoma of the penis is a slowly growing soft tissue neoplasm that rarely arises from the penis.

AIM

The aim of this case is to describe this rare pathology and to underline the importance of differential diagnosis with benign diseases such as Peyronie's disease.

METHOD

We report the case of a 20-year-old man who referred the onset of a progressive left dorsolateral penile curvature (about 60°) started 3 years before. The patient was evaluated with two US examinations that revealed two sites of tunical thickening with normal hemodynamic evaluation. The physical examination demonstrated a dorsal fibrotic plaque of about 2.5 cm.

RESULTS

A juvenile form of Peyronie's Disease was diagnosed, and the patient was scheduled for surgical treatment (plaque's incision/excision and grafting). Intraoperative appearance showed that the great part of the left cavernous body was substituted by a very tough tissue which deeply involved the erectile tissue; intraoperative frozen section was suspicious for mesenchymal epithelioid neoplasm. In order to obtain definitive histological analysis and collect proper informed consent, we preferred to proceed with our original project, applying a dual graft (buccal mucosa and allograft dermal matrix) to cover the wide excised area. The final histological report confirmed the diagnosis of epithelioid sarcoma. Postoperative CT and MRI, at 3 and 6 months from surgery, were negative for metastases. The patient underwent radical intervention after 6 months.

CONCLUSIONS

Epithelioid sarcoma of the penis and Peyronie's Disease can present with similar clinical findings although they obviously entail a different clinical progress. Since the diagnosis of neoplasm can be established only by the pathologist on biopsy specimen, in cases of unusual clinical presentation of Peyronie's disease (especially in young men suffering from a fast-growing penile induration), an early histological assessment should be performed to avoid the possibility of misdiagnosis in case of this poor-prognosis disease and to assure the definitive diagnosis.

Proximal-type epithelioid sarcoma: case report of an unusual presentation

Epithelioid sarcoma, first described by Enzinger in 1970, classically presents in young adults and usually arises in the distal extremities. The proximal-type variant, first described in 1997 as a rare aggressive form of sarcoma, usually arises more proximally. It carries a higher mortality rate than classical limb epithelioid sarcoma and is often resistant to multimodal treatment. We report the case of a 27-year old male who had a delayed diagnosis of proximal-type epithelioid sarcoma of the forearm. This was originally thought to be a necrotising soft tissue infection and was unfortunately metastatic at the time of eventual diagnosis. The clinical and histopathological features of this challenging tumour are discussed and the relevant literature is reviewed.

INI1-deficient tumors: diagnostic features and molecular genetics

Significant progress has been made in understanding the molecular genetic alterations involved in sarcomagenesis. Cytogenetic and molecular studies have identified nonrandom genetic abnormalities, including tumor suppressor gene inactivation. Mutations, deletions, and other somatic alterations in the tumor suppressor gene INI1 (hSNF5; SMARCB1), which encodes a subunit of the SWI/SNF chromatin remodeling complex, were first described in the malignant rhabdoid tumor of infancy. Since then, INI1 has also been implicated in the pathogenesis of additional tumor types including renal medullary carcinomas and epithelioid sarcomas and a subset of epithelioid malignant peripheral nerve sheath tumors, myoepithelial carcinomas, and extraskeletal myxoid chondrosarcomas. As varied as this group appears, they all show loss of INI1 protein expression, a propensity for rhabdoid cytomorphology, and sometimes other overlapping immunohistochemical and histologic findings. We will review the clinicopathologic features of these tumor types and emphasize the clinical utility of INI1 immunohistochemistry in differential diagnosis.

EWSR1 gene rearrangement occurs in a subset of cutaneous myoepithelial tumors: a study of 18 cases

Cutaneous myoepithelial tumors form a clinicopathological spectrum ranging from mixed tumor to myoepithelioma and myoepithelial carcinoma. Recently, EWSR1 rearrangement has been described in a subset of soft tissue myoepithelial tumors, whereas the cutaneous counterparts showed this aberration in a minority of cases. This raises the question whether cutaneous myoepithelial tumors have comparable genetic alterations. We examined 18 cases of cutaneous myoepithelial tumors arising in 7 female and 11 male patients (age range, 34-86 years; mean, 58 years). Eight mixed tumors occurred at the head, and one at the scrotum. Six myoepitheliomas arose at the extremities, and one case each at the back and head. One myoepithelial carcinoma occurred at the cheek. The tumor size ranged from 0.3 to 1.7 cm (mean, 1.0 cm). All mixed tumors and three myoepitheliomas were limited to the dermis. Four myoepitheliomas and the myoepithelial carcinoma involved the subcutis. Mixed tumors and myoepitheliomas were composed of myoepithelial cells with a variable cytomorphology, architecture and stromal background. Ductal structures were seen by definition in mixed tumors. The myoepithelial carcinoma represented an infiltrative dermal neoplasm consisting of atypical spindle cells. Immunohistochemically, all cases tested were positive for EMA and calponin, whereas S100, CK, ASMA and GFAP were expressed in 90%, 80%, 78% and 50% of the cases tested, respectively. By fluorescent in situ hybridization analysis, 7 out of 16 cases (44%) exhibited EWSR1 rearrangement. Four of them were mixed tumors, two were myoepitheliomas and one was a myoepithelial carcinoma, confirming that these lesions represent a spectrum of dermal myoepithelial tumors. Follow-up information, available for five patients (including the patient with a myoepithelial carcinoma), revealed no evidence of disease in all cases (range, 6-72 months). Our study provides a genetic relationship of myoepithelial tumors of the skin with their counterparts in soft tissue, bone and visceral localization by sharing EWSR1 rearrangement.

Primary intranodal epithelioid rhabdomyosarcoma

We report an unusual, rare case of primary epithelioid rhabdomyosarcoma of a lymph node in the parotid basin. A 72-year-old man with a history of squamous cell carcinoma of the forehead and cheek had a 5-cm mobile nontender mass of the parotid tail and right level II region. A positron emission tomography/computed tomography scan confirmed a hypermetabolic soft tissue mass in the right parotid gland. Histologic sections showed an intraparotid lymph node almost completely effaced by a centrally necrotic malignant epithelioid neoplasm consisting of uniform-appearing dyshesive cells exhibiting rhabdoid morphologic features with abundant eosinophilic fibrillary cytoplasm, eccentric nuclei, and prominent nucleoli. Bizarre cells were not seen. In immunohistochemical studies, neoplastic cells expressed desmin and myogenin. Electron microscopy showed a mixture of thick and thin filaments, primitive Z-band formation, and well-formed sarcomeres. Fluorescence in situ hybridization studies for FOXO1, PAX3, and/or PAX7 rearrangements were negative. An extensive clinical and radiologic workup showed no evidence of primary tumor elsewhere. Complete resection of the tumor was performed, and adjuvant chemotherapy was given; patient was disease free 12 months after surgery.

Extrarenal rhabdoid tumor mimicking a sacral peripheral nerve sheath tumor

Extrarenal rhabdoid tumor is a rare, highly aggressive tumor of childhood with a poor prognosis. It represents <1% of pediatric soft tissue malignancies, typically involving infants . Frequently involved extrarenal sites include deep locations of the neck, abdomen, and paraspinal regions. The presence of "rhabdoid" cells is the characteristic histologic feature. Recent discovery of a specific genetic mutation enables a more accurate diagnosis. We present a case in an adolescent of extrarenal rhabdoid tumor arising within the sacral canal. This appears to be the first reported case of an extrarenal rhabdoid tumor arising within the sacral canal and mimicking a peripheral nerve sheath tumor. While rare, this tumor can be included in the radiologic differential diagnosis of peripheral nerve sheath tumors in children.

Successfully treated case of epithelioid sarcoma of the vulva

Epithelioid sarcoma of the vulva is an extremely rare and aggressive tumor. This tumor most commonly occurs on the labia majora in women of reproductive age. The molecular pathogenesis remains largely unknown. Only 20 cases of vulvar epithelioid sarcoma have been reported to date and more than half have had poor outcomes. We report a successfully treated case of vulvar epithelioid sarcoma in a 33-year-old woman. We performed a radical vulvectomy with flap reconstruction. Three years after surgery, the patient remains well, showing no evidence of recurrence. Early tissue diagnosis of vulvar epithelioid sarcoma is essential because this tumor can be clinically misdiagnosed as a benign lesion. Gynecologists should be aware of this rare tumor variant and carefully plan the treatment.

Epithelioid Lesions

Epithelioid variants have been described for most mesenchymal tumors, including leiomyosarcoma, pleomorphic liposarcoma, epithelioid fibrous histiocytoma, and myxofibrosarcoma. Soft tissue tumors that commonly show epithelioid morphology include epithelioid vascular lesions, epithelioid sarcoma, sclerosing epithelioid fibrosarcoma, and epithelioid malignant peripheral nerve sheath tumor. Many of the entities described in this review were originally described as "simulating carcinoma" or "often mistaken for carcinoma" and this pitfall should be considered when evaluating epithelioid lesions in soft tissue. Many epithelioid soft tissue tumors express epithelial antigens to a varying degree and an immunohistochemical panel is essential for correct classification.

Imaging of unusual perineal masses

OBJECTIVE

The purpose of this article is to describe the radiologic features of unusual tumors that occur in the perineum.

CONCLUSION

The perineal space is often overlooked because of the infrequency of abnormalities. Accurate image interpretation and visualization of extent of pathology is important for proper management. Trauma and infectious diseases occur in the acute setting, whereas tumors are common in the chronic setting. Cross-sectional imaging plays a crucial role in depicting perineal anatomy and evaluating the extent of disease.

INI1 immunohistochemical expression in glioblastoma: correlation with MGMT gene promoter methylation status and patient survival

AIMS

INI1 expression and its correlation with MGMT gene promoter methylation status and follow-up was investigated in 77 surgically removed glioblastomas then treated with radiotherapy (RT) or RT plus temozolomide (TMZ).

METHODS

INI1 was determined by immunohistochemistry and MGMT by methylation-specific PCR.

RESULTS

INI1 was expressed in 83.1% of cases. The median overall survival (OS) was 13.6 months in INI1+ tumours and 7.2 months in INI1- tumours. 31.3% of patients with INI1+ tumours were alive compared with 15.4% of patients with INI1- tumours. MGMT methylation was detected in 31.2% of cases. OS was significantly different between patients with methylated tumours and un-methylated tumours (p < 0.04), and between patients with RT+ TMZ and RT alone (p < 0.001). Considering both treatment and MGMT, the difference in OS was significant (p < 0.002). The difference in OS according to MGMT and INI1 was significant (p < 0.04). The longest median OS was recorded among methylated and INI1+ tumours. Among un-methylated tumours, the median OS was 11.1 months in INI1+ and 6.5 months in INI1- tumours. No patients were alive with un-methylated and INI1- tumours.

CONCLUSIONS

Loss of INI1 immunohistochemical expression in glioblastoma may be indicating an underlying molecular aberration accounting for the more aggressive clinical behaviour.

Epithelioid sarcoma of the orbit

Epithelioid sarcoma is an aggressive and rare malignancy first recognized by Enzinger in 1970. It is known most commonly to affect the distal upper extremities in young adults. The classical "distal" form has a male predominance and can also involve other less frequent sites including lower extremities, proximal upper extremities, and the trunk. The "proximal" variant of this tumor is deep seated, tends to occur in older patients and predominantly develops in the pelvis, perineum, and genital tract. In the orbit, only a single report of two cases, which had a typical histopathologic appearance, has been previously published. We present the third case of orbital primary epithelioid sarcoma.

Epithelioid sarcoma and unclassified sarcoma with epithelioid features: clinicopathological variables, molecular markers, and a new experimental model

BACKGROUND

Epithelioid sarcoma (ES) and unclassified sarcoma with epithelioid features (USEF) are clinically and therapeutically unresolved. We compared ES and USEF patients' clinical behavior, treatment, outcome, and molecular marker expression. Furthermore, preclinical ES study models were developed to enable comprehensive benchside investigations.

PATIENTS AND METHODS

A database of ES and USEF patients (n = 116) treated since 1992 was created. A clinically annotated ES-USEF tissue microarray (TMA) was assayed for tumor-related markers. Newly established human and commercially available ES cell lines were characterized and tested in vivo.

RESULTS

ES and USEF patients presenting with localized disease exhibited 22% and 25% local recurrence rates, 35% and 19% nodal metastasis rates, and 41% and 53% distant metastasis rates (median follow-up, 54 months and 39 months, respectively). The 5- and 10-year disease-specific survival rates were 88% and 43% and 52% and 42% (ES and USEF, respectively). TMA immunohistochemistry identified integrase interactor (INI)-1 loss, cancer antigen 125, and p53 nuclear expression as significantly more common in ES than USEF cases. Both cell lines preserved ES morphological and biochemical characteristics in vitro and in vivo; loss of INI-1 was shown to occur in both lines.

CONCLUSIONS

Enhanced knowledge of ES and USEF clinical behavior, marker expression, and molecular determinants, extended via experimental models, will hopefully accelerate development of urgently needed effective targeted therapies for ES and USEF.

Recurrent epithelioid sarcoma in the thoracic spine successfully treated with multilevel total en bloc spondylectomy

Epithelioid sarcoma (ES) is a rare type of soft tissue tumor. The common location of ES is at the extremities and rarely occurs in axial skeleton. Only two cases have been reported so far. Initial wide resection is recommended for the treatment of ES. However, the local recurrent rate is high and repeat surgical resection is still an option for the treatment of the recurrent. In the spine, however, the proper treatment of recurrent ES has not yet been published. Therefore, the objective of this case report is to illustrate the management strategies for the local recurrent ES after initial surgical resection in the thoracic spine. A 14-year-old boy was diagnosed for ES in the thoracic spine for 2 years. He was first treated by surgical resection followed by the chemotherapy and radiotherapy but the disease had progressed and the spine was gradually deformed. He was admitted to our facility with a large soft tissue mass, severe kyphotic deformity and neurological deficit. We removed the tumor en bloc by one-stage posterior only approach. The posterior transpedicular spinal instrumentation and fibular strut graft were used for the reconstruction. On the last follow-up, 2 year after the surgery, the patient remained in good condition. In conclusion, the recurrent ES of the spine can still archive a good oncological outcome with repeat radical resection, but the initial radical resection remains the best treatment option in order to retard the relentless course of this kind of malignancy.

Inflammatory monomorphic undifferentiated sarcoma with distinct clinical and pathological features: a 'new' entity?

AIM

To describe two patients with a highly aggressive, apparently 'new' and rare soft tissue and bone malignancy of childhood and early adult life that we have named inflammatory monomorphic undifferentiated sarcoma.

METHODS AND RESULTS

Two histologically identical tumours located in the proximal humerus and the anterior chest wall of males aged 6 and 31 presented as solitary, painful, tender, necrotising, masses, associated with fever, leukocytosis and negative microbiological cultures. The extensively necrotic resected tumours consisted of large, monomorphic epithelioid cells with vesicular nuclei, prominent eosinophilic nucleoli, and abundant eosinophilic cytoplasm surrounded by numerous neutrophils and eosinophils which formed sterile microabscesses. Immunohistochemical and ultrastructural studies revealed no specific differentiation. Both tumours were very aggressive, with early local recurrence, metastasis to regional and distant lymph nodes and viscera, and no response to several different chemotherapeutic regimens.

CONCLUSION

A careful review of the literature led us to believe that inflammatory monomorphic undifferentiated sarcoma may represent a rare and distinct clinicopathological entity that does not appear to have been previously described.

Liposarcoma: molecular genetics and therapeutics

Sarcomas are a group of heterogeneous tumours with varying genetic basis. Cytogenetic abnormalities range from distinct genomic rearrangements such as pathognomonic translocation events and common chromosomal amplification or loss, to more complex rearrangements involving multiple chromosomes. The different subtypes of liposarcoma are spread across this spectrum and constitute an interesting tumour type for molecular review. This paper will outline molecular pathogenesis of the three main subtypes of liposarcoma: well-differentiated/dedifferentiated, myxoid/round cell, and pleomorphic liposarcoma. Both the molecular basis and future avenues for therapeutic intervention will be discussed.

Fine needle aspiration cytology of epithelioid sarcoma

In this case report, we have described the fine needle aspiration cytology (FNAC) of epithelioid sarcoma (ES) in a 40-year-old female patient who presented with multiple nodular swellings over right forearm and single right axillary lymph node. The FNAC smear showed predominantly dispersed as well as three-dimensional clusters of malignant cells admixed with basement membrane like material. The individual cells were moderately pleomorphic with round to oval nuclei and moderate to abundant amount of cytoplasm. The neoplastic cells have well-defined cytoplasmic borders and intercellular spaces. The excision biopsy of the swelling of the forearm showed ES. The cytology features of ES are characteristic and a preoperative diagnosis is helpful for proper management of the case.

Proximal-type epithelioid sarcoma of the maxilla with metastasis to the scalp: Cytologic findings of an unusual malignant tumor

Epithelioid sarcoma of proximal type (ESPT), a subtype of epithelioid sarcoma, is an uncommon malignant neoplasm of the soft tissue with histo- and cytologic features similar to epithelioid sarcoma, classic type and to the more commonly encountered extra-renal malignant rhabdoid tumor (EMRT). Unlike classic epithelioid sarcoma, ESPT usually involves pelvic, perineal, and genital regions and has an aggressive clinical course. Like EMRT, ESPT can have aberrations of the INI1 gene on chromosome 22q, which results in the loss of INI1 protein expression. We describe here the cytological findings of an ESPT metastatic to the scalp in a 14-year-old boy. Cytological preparations showed a discohesive population of pleomorphic ovoid to polygonal cells with large irregular nuclei and prominent nucleoli. Isolated cells with rhabdoid features were noted. These cells had abundant cytoplasm and occasional intracytoplasmic hyaline inclusions. In the light of the patient's clinical history of a known primary ESPT of the maxilla, the cytologic features were distinct enough to render a diagnosis of a metastatic lesion to the skull.

Immunohistochemistry in the diagnosis of cutaneous neoplasms

In recent years, there has been a significant increase in the number of diagnostic immunohistochemical stains available to pathologists and dermatopathologists. Immunohistochemistry has become an indispensable tool in dermatopathology, not only in diagnosis but also in the treatment and prognostication of cutaneous neoplasms. In this review we attempt to outline current, as well as new, immunohistochemical stains of relevance in the diagnosis and classification of cutaneous neoplasms.

Miscellaneous Pseudotumors and Mesenchymal Tumors of the Female Genital Tract

Benign and malignant soft tissue tumors and pseudotumors can rarely arise anywhere in the female genital tract. Their pathologic features as well as behavior typically overlap with those described in tumors involving typical locations. However, due to their rarity, not infrequently these tumors represent a diagnostic challenge. Their diagnosis should be based on careful gross examination, thorough sampling, and morphologic evaluation, applying a selected immunohistochemical panel and molecular studies. Accurate classification of these tumors is important because their clinical behavior, prognosis, and therapy differ markedly. This article outlines several mesenchymal lesions reported in the female genital tract, encompassing recent histologic, immunohistochemical, and molecular findings, with special emphasis on problems in the differential diagnosis.

Smooth Muscle Tumors of the Female Genital Tract

Smooth muscle tumors are the most common among mesenchymal tumors in the female genital tract. The vast majority of these neoplasms are clinically benign and easy to diagnose. In contrast, leiomyosarcomas are highly aggressive tumors that may pose considerable diagnostic problems when they display unusual (myxoid or epithelioid) morphology, ambiguous histologic features for malignancy, or an unusual anatomic distribution. Diagnostic criteria for these problematic tumors vary depending on the site and type of histologic differentiation, and are based on a combination of 3 major criteria: (1) moderate to severe cytologic atypia; (2) increased mitotic index; and (3) tumor cell necrosis. Certain benign smooth muscle proliferations may show worrisome histologic features or unusual growth patterns, causing concern for leiomyosarcoma. Furthermore, other tumors, including perivascular epithelioid tumors, may mimic leiomyosarcoma. Careful attention to the clinical and anatomic setting, cytologic and architectural features, and immunohistochemical characteristics are helpful in distinguishing these entities. This article discusses conventional smooth muscle tumors as well as unusual subtypes, with emphasis on the diagnostic criteria and problems in differential diagnosis that arise at each site within the female genital tract.

Recent developments in the pathology of renal tumors: morphology and molecular characteristics of select entities

CONTEXT

Renal cell carcinoma is a heterogeneous group of tumors with distinct histopathologic features, molecular characteristics, and clinical outcome. These tumors can be sporadic as well as familial or associated with syndromes. The genetic abnormalities underlying these syndromes have been identified and were subsequently found in corresponding sporadic renal tumors.

OBJECTIVE

To review the recent molecular and genetic advancements relating to sporadic and familial renal carcinomas as well as those related to Xp11.2 translocation-associated renal cell carcinoma and renal medullary carcinoma.

DATA SOURCES

Literature review, personal experience, and material from the University of Chicago.

CONCLUSIONS

Molecular genetic diagnostic techniques will continue to introduce new biomarkers that will aid in the differential diagnosis of difficult cases. The identification of specific signaling pathways that are defective in certain renal tumors also makes possible the development of new therapies that selectively target the aberrant activity of the defective proteins.