Desmoplastic small round cell tumor of the submandibular gland--a rare but distinctive primary salivary gland neoplasm

Desmoplastic Small Round Cell Tumor of the Head and Neck: A Potential Diagnostic Pitfall

Primary desmoplastic small round cell tumor (DSRCT) in the head and neck region is extremely rare. There is limited information about its clinicopathological characteristics, prognosis, and treatment modalities. The purpose of this study is to provide a comprehensive review of DSRCT occurring primarily in the head and neck, to demonstrate its peculiar morphology and immunohistochemical expression, and to address the differential diagnoses. A total of 25 cases were collected after a thorough review of the relevant literature. DSRCT was most frequently reported in the major salivary glands, followed by the eyes. Furthermore, some cases were misinterpreted as poorly differentiated carcinoma, Ewing sarcoma, and olfactory neuroblastoma. Diagnosing DSRCTs in the head and neck can be very challenging due to their rarity in this location, overlapping morphology, and immunohistochemistry. In these cases, following a systemic approach helps to solve diagnostic problems.

Desmoplastic Small Round Cell Tumor of the Head and Neck: A Clinicopathological, Immunohistochemical and Molecular Analysis of Three Cases with Literature Review

Desmoplastic small round cell tumor (DSRCT) is a rare aggressive malignancy typically originating from the abdominal or pelvic cavity. DSRCT presenting as a primary head and neck tumor has rarely been described in the literature. We present three cases of DSRCT arising in the head and neck to further characterize its clinicopathological features. All three patients were male and aged 36, 30 and 17 years. The involved sites included the orbit (1 case) and submandibular gland (2 cases). The tumors ranged in size from 2.4 to 3.5 cm (mean, 2.1 cm). Histologically, all tumors showed irregular-shaped, variable-sized nests of small round cells deposited in an abundant desmoplastic stroma. Tumor cells contained scant amounts of eosinophilic cytoplasm and small hyperchromatic nuclei with inconspicuous nucleoli. Immunohistochemically, the tumors were positive for keratin (AE1/AE3) (3/3), desmin (3/3), vimentin (2/2), NSE (1/1) and EMA (1/1). Fluorescence in situ hybridization (FISH) analysis demonstrated the presence of EWSR1 and WT1 rearrangements in all three cases. All patients received surgery and adjuvant chemotherapy and/or radiotherapy. There was no evidence of recurrence and metastasis in two patients, and the third suffered lung metastasis. DSRCT arising in the head and neck represents an extremely rare condition. It is easily mistaken as poorly differentiated carcinoma due to similar morphology and expression of epithelial markers. Immunohistochemistry assay in conjunction with molecular detection of EWSR1::WT1 fusion will be helpful for arriving at an accurate diagnosis to avoid misdiagnosis and inappropriate treatment.

Desmoplastic Small Round Cell Tumor of the Submandibular Gland: A Case Report and Literature Review

Desmoplastic small round cell tumor (DSRCT) is a rare and aggressively malignant tumor mostly occurring in the abdominal and pelvic cavity of young patients. However, few cases had been reported concerning DSRCT occurring in the head and neck region. We presented a rare case of DSRCT of the right submandibular in a 25-year-old man. MRI revealed a 3 × 2-cm solid nodule located in the right submandibular, and physical examination showed no other occupying lesion elsewhere. Histologically, the tumor was composed of various-sized small round cell nests, embedded in an abundant desmoplastic stroma. Immunohistochemically, the tumor cells were typically positive for epithelial (CK and EMA), mesenchymal (vimentin and desmin), and neuroendocrine (CD56, NSE, Syn, and CgA) markers, but negative for WT1. Fluorescence in situ hybridization revealed the presence of a break apart involving the Ewing sarcoma (EWS) gene. The patient received chemotherapy and radiotherapy and relapsed after 19 months of follow-up. DSRCT of the submandibular gland is rare, and the diagnosis of this tumor in an uncommon location relies on the histomorphology, immunophenotype, and EWS gene translocation detection. Differential diagnosis including primary salivary gland tumors and the other small round cell tumors needs to be excluded.

Desmoplastic Small Round Cell Tumors: A review with focus on clinical management and therapeutic options

Desmoplastic Small Round Cell Tumors (DSRCTs) are an entity of rare, aggressive soft tissue sarcomas described by Gerald and Rosai in 1989. It predominantly affects male adolescents and young adults, with a peak incidence between an age of 20 and 30 years. Typically, DSRCT demonstrate as multiple small tumor nodules within the abdominal cave, retroperitoneum and pelvis. In more than 50% of the cases, the neoplasm presents metastatic at the timepoint of diagnosis. Histologically, DSRCTs have a characteristic morphology with sharply demarcated islands of uniform small round cells in abundant desmoplastic stroma organized in loose extracellular matrix. Immunohistochemistry reveals a polyphenotypic differentiation with co-expression of epithelial, myogenic, mesenchymal and neural markers. The morphology is highly variable and can hinder diagnosis. The most consistent molecular characteristic of DSRCT is the reciprocal t(11;22)(p13q12) translocation. This mutation leads to a formation of the EWSR1-WT1 fusion oncogene, which encodes for a chimeric protein with transcriptional regulatory activity and is regarded as driving source of the disease. To date, there is no standardized concept for clinical management, staging and treatment. Patients receive an aggressive multimodal therapeutic approach consisting of chemotherapy, radical surgical procedures, hyperthermic, intraperitoneal chemotherapy (HIPEC) and radiation. New targeted therapies are used in experimental settings as salvage therapy. So far, none of these therapies showed significant long-term success. This review gives an overview of diagnostic difficulties and pitfalls, discusses therapeutic strategies and highlights options for clinical management.

Desmoplastic Small Round Cell Tumor of Parotid Gland: A Rare Entity With Diagnostic Challenge

Desmoplastic small round cell tumor (DSRCT) is a rare malignant mesenchymal neoplasm that typically affects young patients and presents as large intraabdominal masses. We report a rare case of parotid gland DSRCT in a 38-year-old man. The tumor cells were large sized and form irregular nests embedded in abundant desmoplastic stroma. Immunohistochemically, the tumor cells were positive for cytokeratin, GATA3, p40, and p63. Working differential diagnosis included squamous cell carcinoma, myoepithelial carcinoma, hyalinizing clear cell carcinoma, NUT (nuclear protein of the testis) carcinoma, and adamantinoma-like Ewing sarcoma. The characteristic morphologic features and presence of EWSR1-WT1 gene fusion are diagnostic of DSRCT. Salivary gland DSRCT is an exceedingly rare entity, with only 6 cases reported in the literature.

Mesenchymal Tumors with EWSR1 Gene Rearrangements

Among the various genes that can be rearranged in soft tissue neoplasms associated with nonrandom chromosomal translocations, EWSR1 is the most frequent one to partner with other genes to generate recurrent fusion genes. This leads to a spectrum of clinically and pathologically diverse mesenchymal and nonmesenchymal neoplasms, variably manifesting as small round cell, spindle cell, clear cell or adipocytic tumors, or tumors with distinctive myxoid stroma. This review summarizes the growing list of mesenchymal neoplasms that are associated with EWSR1 gene rearrangements.

Desmoplastic small round cell tumor of the parotid gland-report of a rare case and a review of the literature

BACKGROUND

Desmoplastic small round cell tumor (DSRCT) is a rare soft tissue tumor that generally involves the retroperitoneum, pelvis, omentum and mesentery in younger patients. However, extra-abdominal DSRCT is very rare.

CASE PRESENTATION

A 49-year-old Japanese man noticed a mass in the right parotid gland. Ultrasound examination revealed a solid tumor about 2 cm in diameter. Computed tomography (CT) of the whole body revealed no other tumors or lymph node swelling. Superficial parotidectomy was performed. Histologically, the tumor was composed of various-sized tumor cell nests in an abundant fibromyxoid and collagenous background. The tumor cells were small to medium-sized. Immunohistochemistry showed that the tumor cells were immunoreactive for epithelial markers and desmin. They also showed strong nuclear staining with a Wilms tumor 1 (WT1) antibody detecting the C-terminal region (C-WT1), but not the N-terminal region (N-WT1). We also performed 3'/5' expression imbalance assay based on reverse transcription polymerase chain reaction (RT-PCR) to determine whether aberrant WT1 gene expression was present. This tumor was found to lack 5'-regional expression of the WT1 gene, as well as immunoreactivity with the N-WT1 antibody. Finally, fluorescence in situ hybridization (FISH) and RT-PCR analyses revealed the presence of a gene showing fusion between exon 7 of EWSR1 and exon 8 of WT1. The tumor was diagnosed as a DSRCT of the right parotid gland. The patient has been followed for 3 years without recurrence or metastasis.

CONCLUSIONS

Although DSRCT in the salivary gland is extremely rare, it should be included in the differential diagnosis of poorly differentiated salivary gland neoplasms, especially with a fibromyxoid background. Pathologists should bear in mind that DSRCT may occur in major salivary glands and should perform immunohistochemistry with appropriate antibodies, not only those against keratin and desmin, but also one detecting the C-terminal region of WT-1. Furthermore, molecular detection of EWSR1-WT1 fusion gene conclusively confirmed the diagnosis of DSRCT in this uncommon location.

Desmoplastic Small Round Cell Tumor

Desmoplastic small round cell tumor (DSRCT) is an aggressive small round cell neoplasm which predominantly occurs intra-abdominally in adolescents and young adults with a male predominance, and which is characterized by a recurrent t(11;22)(p13;q12) translocation leading to formation of the EWSR1-WT1 fusion gene, which generates a chimeric protein with transcriptional regulatory activity. Histologically, DSRCT has a characteristic morphology, of islands of monotonous small cells within prominent sparsely cellular fibroblastic stroma, and immunohistochemically it shows polyphenotypic multidirectional differentiation, with expression of epithelial, muscle, and neural markers. However, DSRCT can arise more rarely in other sites and exhibit a spectrum of both histologic features and immunoprofile, which may confuse diagnosis with other small round cell neoplasms. Correct diagnosis is important to ensure correct treatment and prognostication; DSRCT are almost universally fatal neoplasms with patients usually succumbing to disease within the first 2 years of diagnosis. While combination treatment strategies can confer a survival benefit, the overall prognosis remains poor. Further insight into the tumorigenic molecular changes generated by the fusion oncogene may lead to the generation of specific targeted therapies. We review DSRCT, discussing morphology and immunohistochemistry, molecular genetic findings, potential targeted treatments, and the differential diagnosis.

Neuroendocrine neoplasms of the sinonasal region

Neuroendocrine neoplasms of the sinonasal region, which are relatively uncommon but clinically very important, are reviewed here in the light of current knowledge. Using a definition for neuroendocrine based on phenotypic, histologic, immunohistochemical, and electron microscopic features rather than histogenetic criteria, sinonasal neuroendocrine carcinomas are examined with a particular emphasis on the small-cell and large-cell subtypes. This is followed by revisiting olfactory neuroblastoma because it is also a tumor that shows a neuroendocrine phenotype. Kadish clinical and Hyams histologic grading systems as prognosticators of olfactory neuroblastoma are also considered in detail. Finally, controversies regarding sinonasal undifferentiated carcinoma as a neuroendocrine tumor are discussed and a possible relationship with high-grade olfactory neuroblastoma is explored. Genetic events and current management of these tumors are also outlined. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2259-E2266, 2016.

Primary desmoplastic small round cell tumor of upper cervical lymph nodes

Desmoplastic small round cell tumors (DSRCT) are rare malignancies that typically arise in the abdominopelvic cavities. They are very uncommon in the head and neck region. We present a case of an 11-year-old Caucasian male with a primary cervical lymph node tumor in the neck. Fine-needle aspiration cytology, histopathologic examination, immunohistochemical staining, and molecular genetic testing led to the diagnosis of DSRCT. Due to the very limited number of cases reported and the lack of staging criteria, the preferred management approach remains uncertain.

Recent advances in the diagnostic pathology of salivary carcinomas

This review concentrates on the most important developments since the WHO classification of 2005. In particular, the identification of specific translocations is revolutionising the way salivary tumours are considered and will have a major impact on future diagnostic practice. This is true so far in four malignancies: mammary analogue secretory, mucoepidermoid, adenoid cystic and hyalinising clear cell carcinomas. In each, the gene rearrangement is found in 80 % or more of cases. Two 2014 publications have added further possible candidates with molecular abnormalities to the list (cribriform adenocarcinoma of the tongue and minor salivary glands and epithelial-myoepithelial carcinoma), but these findings have yet to be confirmed by other investigators. The advances in molecular pathology have also allowed re-evaluation of the morphology; for example, it is now realised that the histological spectrum of hyalinising clear cell carcinoma includes intracellular mucin in over half of cases, as well as tumours with only scanty clear cells. In a separate development, it is now proposed that salivary duct carcinoma can be subdivided along molecular lines, in ways analogous to breast cancer, suggesting new therapeutic prospects in an otherwise highly aggressive malignancy.

Primary sarcomas of the salivary glands: case series and literature review

BACKGROUND

Mesenchymal malignancies of salivary origin are rare and are histologically diverse. We reviewed our experience with these tumors, as well as the published literature, with an emphasis on treatment modalities and prognosis.

METHODS

We identified 17 patients treated for malignant mesenchymal cell tumors at The University of Texas MD Anderson Cancer Center between 1990 and 2007. We compared our results to the literature from January 1990 to July 2010.

RESULTS

Tumors were located primarily in the parotid gland and were primarily T1 tumors (<5 cm). All patients were treated with surgical resection, and 13 patients were given adjuvant therapy. Seven patients (41%) had recurrence, and 4 developed distant metastases. The overall 5-year and 10-year survival rates were 42% and 20%, respectively.

CONCLUSIONS

Our case series and literature review show that sarcomas of the salivary glands have a high rate of recurrence and are associated with a poor prognosis.

Characteristic imaging features of desmoplastic small round cell tumour

BACKGROUND

Desmoplastic small round cell tumour (DSRCT) is a rare malignant neoplasm. Its radiological features have rarely been described.

OBJECTIVE

To assess the CT parameters characteristic of DSRCT. We also report our experience with combined FDG PET/CT in staging and follow-up for DSRCT.

MATERIALS AND METHODS

The pretreatment diagnostic CT's of 65 patients with DSRCT were evaluated. Pertinent imaging findings were catalogued, with histopathology or serial follow-up studies as reference standard. Combined FDG PET/CT examinations of 11 of these patients who underwent pretreatment imaging were also reviewed.

RESULTS

Sixty-two patients presented with primary intra-abdominal disease; three had primary extra-abdominal tumours at presentation. The most common imaging finding of patients with intra-abdominal DSRCT was multiple peritoneal soft tissue masses, with a dominant mass in the retrovesical or rectouterine location in more than half of the cases. Forty percent had metastatic disease to the liver, lungs, spleen or bones at diagnosis. FDG PET/CT accurately detected 97.4% of all DSRCT lesions.

CONCLUSION

DSRCT typically presents as a large abdominopelvic mass with widespread peritoneal involvement predominantly in young males. Familiarity with its radiological features can help guide diagnosis and treatment. Functional imaging with PET/CT offers advantage over anatomical imaging for accurate disease staging.

Paratesticular desmoplastic small round cell tumour: an unusual tumour with an unusual fusion; cytogenetic and molecular genetic analysis combining RT-PCR and COBRA-FISH

Desmoplastic small round cell tumour is a rare malignant tumour with a male to female ratio of 4:1. It manifests mostly at serosal sites. Here we present a case of a 28-year-old male patient, who presented with a fast growing paratesticular mass. On biopsy nests and cords of small round cells, without a clear morphological lineage of differentiation were seen. Occasionally desmoplatic small round cell tumour shows different lines of differentiation. An unequivocal histological diagnosis might be difficult in such cases. Here we demonstrate by a combination of methods the characteristic immunohistochemical profile and - albeit unusual - molecular background and discuss the eventual link with Ewing sarcoma.Immunohistochemical studies showed a membranous staining of Keratine AE1/3 and a dot-like staining of Desmine, confirming its diagnosis. Using COBRA-FISH following a metaphase approach we demonstrated a balanced translocation, t(11;22)(p13;q12) and in RT-PCR formation of the EWSR1-WT1 fusion product, a specific translocation of desmoplastic round cell tumour. The fusion involves exon 9 of EWSR1 to exon 8 of WT1, an unusual fusion product, though earlier described in a case of a desmoplastic small round cell tumour of the hand. The EWSR1-WT1 chimera seems to function as an oncogenic transcription factor. Here the zinc finger domain of the WT1 acts with affinity with certain promoter domains influencing the expression of various downstream proteins such as: PDGFA, PAX2, insulin-like growth factor 1 receptor, epidermal growth factor receptor, IL2 receptor beta, BAIAP3, MLF1, TALLA-1, LRRC15 and ENT. We discuss their potential oncogenic roles and potential therapeutic consequences.