Dedifferentiated acinic cell carcinoma of the parotid gland with myoepithelial features

Acinic cell Carcinoma with high-grade Squamoglandular and Chondrosarcomatous Transformation Mimicking 'Carcinosarcoma ex-pleomorphic Adenoma': A Wrinkle in the Proposed Nomenclature Revision for Sarcomatoid Salivary Gland Neoplasms

While acinic cell carcinoma (AciCC) can undergo high-grade transformation (HGT) to high-grade adenocarcinoma or poorly differentiated carcinoma, other morphologies such as spindle cell/sarcomatoid carcinoma are rare and not well-characterized. We herein report a novel case of AciCC with squamoglandular and chondrosarcomatous HGT mimicking a so-called 'carcinosarcoma ex-pleomorphic adenoma'. The patient is an 81-year-old male with a two-month history of neck swelling and referred otalgia who presented with a left parapharyngeal space mass extending into retropharyngeal space and pterygoid muscles. On resection, the tumor showed considerable morphologic diversity with high-grade serous and mucous acinar components as well as cribriform to solid apocrine-like components with comedonecrosis and squamous differentiation, all of which were embedded in a chondromyxoid background ranging from paucicellular and bland to a high-grade chondrosarcoma/pleomorphic sarcoma-like appearance. Only a minor conventional AciCC component was noted. Immunostains were negative for AR and only focally positive for GCDFP-15 arguing against a true apocrine phenotype, while PLAG1 and HMGA2 were negative arguing against an antecedent pleomorphic adenoma. On the other hand, SOX-10, DOG-1 and PAS after diastase highlighted serous acinar differentiation, and mucicarmine, and NKX3.1 highlighted mucous acinar differentiation. NR4A3 immunohistochemical staining and NR4A3 fluorescence in situ hybridization were positive in the carcinomatous and sarcomatoid components while sequencing analysis of both components revealed identical alterations involving TP53, PIK3CB, ARID1A, and STK11. This unique case warrants caution in designating all salivary sarcomatoid carcinomas with heterologous elements as part of the 'carcinoma ex-pleomorphic adenoma' family.

NR4A3 Immunohistochemistry Reliably Discriminates Acinic Cell Carcinoma from Mimics

Acinic cell carcinoma (AciCC) harbors a recurrent t(4;9)(q13;q31) translocation, which leads to upregulation of Nuclear Receptor Subfamily 4 Group A Member 3 (NR4A3). Previous work on tissue microarrays suggests that NR4A3 immunohistochemistry (IHC) may be useful in the diagnosis of AciCC. Thus far, only a single study has evaluated the utility of NR4A3 immunohistochemistry (IHC) in the diagnosis of AciCC, using a tissue microarray to assess most non-AciCC tumor types. Herein we evaluate the diagnostic performance of NR4A3 IHC for AciCC in a large cohort of 157 salivary gland tumors, using whole tissue sections. The cohort consisted of 37 AciCC (6 of them (16%) with high grade transformation), 30 secretory carcinomas (SC), and 90 additional salivary gland tumors, including mucoepidermoid carcinomas (MEC), polymorphous adenocarcinomas (PAC), pleomorphic adenomas (PA), salivary duct carcinomas (SDC), and adenoid cystic carcinomas (AdCC). NR4A3 nuclear staining by IHC was considered positive if present in more than 5% of tumor cells. Overall, 92% of AciCC (34/37) expressed NR4A3 by IHC, with strong (89%) or moderate (3%) nuclear staining, yielding a sensitivity of 92%. IHC detected NR4A3 expression in all cases of recurrent/metastatic AciCC and tumors with high grade transformation. Importantly, all SC were negative for NR4A3 IHC, with no staining in 28/30 cases and weak focal staining, in < 5% of cells, in 2/30 (7%). Similarly, all MEC (20/20), SDC (20/20) and AdCC (10/10) were negative for NR4A3 by IHC, as were most PA (18/20; 15%) and PAC (18/20; 5%). Two PA and two PAC showed multifocal expression of NR4A3 in more than 5% of cells, of weak intensity in 3 cases and moderate in 1 PAC, yielding an overall specificity of 97% for NR4A3 IHC for the diagnosis of AciCC. In conclusion, NR4A3 is a highly sensitive and specific immunohistochemical marker for AciCC; moderate to strong and/or diffuse NR4A3 expression is a consistent and diagnostic feature of AciCC.

High grade transformation of salivary gland acinic cell carcinoma with emphasis on histological diagnosis and clinical implications

Acinic cell carcinoma (ACC) is commonly thought of as a low grade malignant salivary neoplasm, and possibly has the best prognosis of all salivary malignancies with a 10-year survival of almost 90%. High grade transformation (HGT) in these tumours is a relatively rare event but is increasingly being reported. HGT (formerly referred to as dedifferentiation) in acinic cell carcinoma has shown to drastically reduce the survival rates and its recognition is imperative as more aggressive clinical management is needed. We report a case of parotid acinic cell carcinoma in a 82-year old woman where the fine needle aspirate suggested either pleomorphic adenoma or the possibility of carcinoma ex pleomorphic adenoma. Per-operatively it became clear that the facial nerve was involved and the tumour mass was debulked only. The histology showed an acinic cell carcinoma with foci of high grade differentiation (ACC-HGT). We describe the histology of HGT in ACC and the most common differential diagnoses. We emphasise the need of very generous sampling of the tumour, as to recognise any area of high grade transformation, some of which can be very small. A literature review of ACC-HGT as well as HGT in other salivary gland neoplasms is presented. HGT of ACC greatly thus influences the macroscopical and microscopical evaluation of the specimen but also, given the high incidence of metastases and morbidity, carries significant treatment implications.

Clinicopathologic and Immunophenotypic Characterization of 25 Cases of Acinic Cell Carcinoma with High-Grade Transformation

Acinic cell carcinoma (AiCC) with high-grade transformation is a rare variant of AiCC composed of both a conventional low-grade (LG) AiCC and a separate high-grade (HG) component. We describe here, the clinicopathologic and immunohistochemical features of 25 cases diagnosed between 1990 and 2015. Available tissue was analyzed and compared with a cohort of pure LG AiCC for the morphologic and immunophenotypic profile. Incidence was higher in females (1.8:1) than males with an overall mean age at presentation of 63.2 years. All tumors occurred in the parotid gland including 76% with facial nerve trunk and branches involvement. Most patients were treated with extensive resection and adjuvant therapy. Local recurrence or distant metastasis occurred in most patients, with 72.7% dead with disease (mean 2.9 years) and 3 patients alive with disease (mean 2.4 years). The majority of the tumors were composed of a LG microcystic AiCC and a HG component consisting of invasive lobules of undifferentiated cells with predominantly solid, cribriform, and glandular patterns. Acinic differentiation was still present in HG areas but aggressive features such as perineural invasion (76%), lymphovascular invasion (62%), positive margins (72%), high mitotic rate, atypical mitoses and/or comedonecrosis (86%) were easily identified. Compared to the pure LG AiCC, the cases with HG transformation showed significantly increased expression of cyclin-D1, p53 and Ki-67. Most HG areas of AiCC expressed membranous β-catenin (92%) and were negative for p63 (three cases were focally positive), S100, SMA, androgen, and estrogen receptors. DOG1 expression was present in all LG AiCC tested with retained expression in 91% of cases with HG transformation, supporting acinic differentiation in the HG foci. Recognition of AiCC with high-grade transformation is imperative as more aggressive clinical management is warranted.

Salivary gland myoepithelial carcinoma

Salivary gland myoepithelial carcinoma (MC) or malignant myoepithelioma is a rare entity. MC usually presents as a slow-growing painless mass arising in the parotid gland, but may involve other salivary glands. This tumour may be particularly locally aggressive, but its clinical and biological features are not yet fully understood. MC may arise from pre-existing benign lesions, such as pleomorphic adenomas or benign myoepitheliomas, or may arise de novo. It usually affects patients over 50 years old, with no gender preference. Because it is often asymptomatic, the presentation and diagnosis can be delayed by months, even years. The current WHO classification considers MC to be an intermediate- to high-grade malignancy. Other published data suggest it is likely to be a high-grade neoplasm, consistent with its aggressive behaviour. Its epidemiology, histopathological features, immunohistochemical profile, clinical behaviour and optimal management are not well understood. Following review of the current literature we aim to address these.

"Dedifferentiation" and high-grade transformation in salivary gland carcinomas

"Dedifferentiation" and/or high-grade transformation (HGT) has been described in a variety of salivary gland carcinomas, including acinic cell carcinoma, adenoid cystic carcinoma, epithelial-myoepithelial carcinoma, polymorphous low-grade adenocarcinoma, myoepithelial carcinoma, low-grade mucoepidermoid carcinoma and hyalinizing clear cell carcinoma, although the phenomenon is a rare event. Recent authors tend to preferably use the term HGT instead of "dedifferentiation" in these cases. HGT-tumors are composed of conventional carcinomas juxtaposed with areas of HG morphology, usually either poorly differentiated adenocarcinoma or "undifferentiated" carcinoma, in which the original line of differentiation is no longer evident. The HG component is generally composed of solid nests, sometimes occurring in cribriform pattern of anaplastic cells with large vesicular pleomorphic nuclei, prominent nucleoli and abundant cytoplasm. Frequent mitoses and extensive necrosis is evident. The Ki-67 labeling index is consistently higher in the HG component. p53 abnormalities have been demonstrated in the transformed component in a few examples, but the frequency varies by the histologic type. HER-2/neu overexpression and/or gene amplification is considerably exceptional. The molecular-genetic mechanisms responsible for the pathway of HGT in salivary gland carcinomas largely still remain to be elucidated. Salivary gland carcinomas with HGT have been shown to be more aggressive than conventional carcinomas with a poorer prognosis, accompanied by higher local recurrence rate and propensity for cervical lymph node metastasis, suggesting the need for wider resection and neck dissection.

Dedifferentiated leiomyosarcoma: clinicopathological analysis of 18 cases

AIMS

To clinicopathologically characterize the dedifferentiated variant of leiomyosarcoma in a series of 18 cases.

METHODS AND RESULTS

Dedifferentiated leiomyosarcoma was defined as showing features of low-grade leiomyosarcoma associated with a discrete undifferentiated component lacking morphological or immunophenotypic features of myogenic differentiation. Tumours developed in 11 women and seven men, with an age range of 16-84 years (median, 64 years). Sites were retroperitoneum (eight cases), limbs (four), trunk (two) uterus (two), and paratesticular and prostate (one each). In 17 cases, dedifferentiation occurred de novo in the primary tumour. Tumour size ranged from 50 to 280 mm (median: 120 mm). Histologically, most showed discrete transition from well-differentiated smooth muscle morphology to high-grade pleomorphic morphology with no smooth muscle differentiation. Unusual features in the dedifferentiated component (epithelioid and rhabdomyoblast-like morphology) were present in three cases. Heterologous osseous or chondro-osseous elements were present in two cases. Dedifferentiated areas were negative for myogenic markers in all cases. Follow-up for 13 cases (median, 36 months) showed local recurrence in 38% (5/13). So far, three patients have died of disease (median survival, 8 months), and metastasis developed in five of 13 cases.

CONCLUSIONS

Dedifferentiated leiomyosarcoma has morphological parallels with other types of dedifferentiated sarcoma, and is clinically aggressive.

Current concepts on dedifferentiation/high-grade transformation in salivary gland tumors

The concept of dedifferentiation had previously been used in salivary gland carcinomas. Recently, the term “high-grade transformation” was introduced for adenoid cystic carcinoma, acinic cell carcinoma, epithelial-myoepithelial carcinoma, and polymorphous low-grade adenocarcinoma and may better reflect this phenomenon, although transformation into moderately differentiated adenocarcinoma (i.e., not “high grade”) has also been described. Among the immunohistochemical markers, Ki-67 seems to be the only one that can help distinguish between the conventional and transformed components; however, the combination of morphological criteria is still sovereign. The overexpression of p53 was observed in the transformed component in all tumor types studied, despite few cases having been demonstrated to carry mutations or deletions in TP53 gene. Genetic studies in salivary gland tumors with dedifferentiation/high-grade transformation are rare and deserve further investigation. This paper aims at providing an overview on the recent concepts in histopathological classification of salivary gland tumors, complemented by immunohistochemical and genetic findings.

Histologic grading and prognostic biomarkers in salivary gland carcinomas

Both the variety and rarity of salivary gland carcinomas pose challenge for using histologic grade and biomarkers to predict outcome. Mucoepidermoid carcinoma is the histologic subtype for which grading is most prognostically and therapeutically relevant. This tumor is graded using standard schemes in a 3-tier manner with the intermediate-grade category shows the most variability between grading systems and thus the most controversy in management. The t(11;19)(q21; p13) MECT1-MAML2 translocation may be an objective marker that can help to further stratify difficult cases. Adenoid cystic carcinomas are graded based on pattern with solid areas correlating with a worse prognosis. Occasionally, adenoid cystic carcinomas may undergo transformation to highly aggressive pleomorphic high-grade carcinomas with frequent nodal metastases. Comparative genomic hybridization has revealed several chromosomal regions (such as 1p32-p36, 6q23-q27) of prognostic interest in adenoid cystic carcinoma. Carcinoma ex-pleomorphic adenoma is actually a category of tumors rather than a single tumor type with both aggressive and indolent versions. These tumors should be further qualified as to type/grade of carcinoma and extent, as intracapsular and minimally invasive tumors behave favorably. Acinic cell carcinomas, although generally considered low grade, can recur, metastasize, or even prove lethal in a significant number of cases suggesting amenability to a grading scheme to separate these biologic groups. Although aggressive histologic parameters (anaplasia, necrosis, and mitoses) are predictive of poor outcome, a standard grading scheme does not yet exists. Acinic cell carcinomas can also undergo high-grade transformation.

Anaplastic myoepithelial carcinoma of the sinonasal tract: an underrecognized salivary-type tumor among the sinonasal small round blue cell malignancies? Report of one case and a review of the literature

We present a 45 year old female patient with a nasal carcinoma showing high-grade/anaplastic histomorphological features and with a distinct myoepithelial immunohistochemical phenotype including positivity for smooth muscle actin, p63, S100 protein with no sustentacular pattern, calponin, cytokeratin 14, vimentin and cytokeratins (AE1-3 and CK5/6). A minority (<5%) of the cells showed focal and variable immunoreactivity for EMA with no cuticular/canalicular pattern. Bcl-2, CD99, CD117 and CD56 were variously positive, but chromogranin and synaptophysin were negative. Weak to moderate nuclear p53 immunoreactivity was seen in 50% of tumor cells. Mib-1/Ki-67 showed an average proliferation of 60-70%. Fluorescent in situ hybridization revealed no EWS-gene translocation. In situ hybridization for EBER was negative.

Epithelial-myoepithelial carcinoma with high grade transformation

Epithelial-myoepithelial carcinoma (EMC) is a rare salivary gland tumor of presumed intercalated duct origin with a low risk of metastasis and mortality. Factors shown to affect behavior include positive margins, vascular invasion, necrosis, and myoepithelial anaplasia. The latter category and dedifferentiated EMCs have been separated on the basis of presumed myoepithelial versus ductal origin, respectively. Three additional cases of typical EMC with transition to high-grade carcinoma are presented. Two of the tumors were stained with CAM5.2, 34betaE12, cytokeratin 14, p63, S100, calponin, smooth muscle actin, and muscle-specific actin. All tumors showed a gradual transition to a high-grade carcinoma from an EMC, each composed of clear cells even in the high-grade regions. One case also showed a discrete area with ductal lumina and another had plasmacytoid morphology. Squamous differentiation was seen in all cases as well. A consistent immunostaining pattern was not noted. Areas with focal lumina were diffusely positive for CAM5.2 only. Areas with clear cells showed patchy S100 positivity only, whereas cytokeratin 14 and 34betaE12-stained squamous pearls. The case with plasmacytoid morphology was diffusely positive for p63. No immunoexpression was noted with smooth muscle actin, muscle-specific actin, or calponin. It was not possible to convincingly separate the high-grade component in these cases into ductal dedifferentiated EMC versus myoepithelial. Recently, there has been a move to abandon the term "dedifferentiation" in favor of "high-grade transformation" in other salivary gland malignancies. We report these 3 such cases, review the literature and propose that these lesions be regarded as "EMC with high-grade transformation."

Fine-needle aspiration of dedifferentiated acinic cell carcinoma: Report of a case with cyto-histological correlation

Dedifferentiated Acinic Cell Carcinoma (DAcCC) is a rare salivary gland malignancy. It has a high tendency to recur and metastasize and thus has a poor prognosis. So far, to our knowledge, only one case of DAcCC has been reported in the cytology literature. Herein, we describe a second case of DAcCC from a fine-needle aspiration (FNA) along with its subsequent histological correlation.

Mucoepidermoid carcinoma with spindle cell change: a low-grade lesion potentially mistaken for sarcomatoid dedifferentiation

An unusual case of mucoepidermoid carcinoma (MEC) of intraoral minor salivary gland origin with spindled morphology was presented. A fascicular stream of bland spindle cells from typical MEC areas amounted to more than 70% of the tumor. Spindle population had features consistent with immunohistochemical and ultrastructural profiles of intermediate cells and lacked overexpression of p53 and cyclin D1. There was no difference in the Ki-67 index between two distinct components. Awareness of extensive spindle cell change replacing a significant portion of low-grade MEC is crucial to avoid an erroneous interpretation of dedifferentiated sarcomatoid transformation.

Association of low-grade endometrioid carcinoma of the uterus and ovary with undifferentiated carcinoma: a new type of dedifferentiated carcinoma?

Low-grade endometrioid carcinomas, either of the endometrium or the ovaries, usually have an excellent prognosis. The association of this type of tumor with undifferentiated carcinoma is rare. In this study, we present the clinicopathologic features of 25 such cases. The age of the patients ranged from 30 to 82 years (median, 51 years). At presentation, the patients had either vaginal bleeding or pelvic pain. The endometrioid carcinoma involved the endometrium in 14 cases, the endometrium and 1 or both ovaries in 9 cases, and the ovaries in 2 cases. Undifferentiated carcinoma associated with low-grade endometrioid carcinoma was found at presentation in 19 grade 1 or 2 endometrioid carcinomas: 15 in the endometrium and 5 in the ovary. In one of these cases, undifferentiated carcinoma was found in the endometrium and the ovary. Undifferentiated carcinoma was found after resection of low-grade endometrioid carcinoma in six cases, involving the retroperitoneum, pelvis, vagina, or liver. The undifferentiated carcinoma was composed exclusively of diffuse sheets and solid nests of epithelial cells in l0 cases. Epithelial cells with isolated foci of keratinization were seen in nine cases and rhabdoid cells in a myxoid background in six cases. Twenty-four patients were treated with total abdominal hysterectomy and with bilateral salpingo-oophorectomy. Twenty-two patients received additional therapy as follows: chemotherapy (), radiotherapy (), and tamoxifen (). Follow-up showed that 15 patients died of disease in 1 to 60 months (median, 6 months), and 5 patients are alive with progressive disease with a follow-up between 6 and 8 months; 1 patient is alive with no evidence of disease at 104 months. In four cases, the diagnosis was made recently, with short follow-ups of 3 and 4 months. Foci of undifferentiated carcinoma may be confused with solid endometrioid adenocarcinoma erroneously leading to the diagnosis of a grade 3 or a significantly less aggressive grade 2 endometrioid carcinoma. The recognition of undifferentiated carcinoma in an otherwise low-grade endometrioid adenocarcinoma is extremely important because it indicates aggressive behavior. In asynchronous cases, being aware of this association can explain the absence of a second primary.

Sinonasal acinic cell carcinoma: a clinicopathologic study of four cases

BACKGROUND

Acinic cell carcinoma is a low-grade malignant epithelial salivary gland neoplasm with a predilection for the parotid gland. To date, only 11 cases of sinonasal acinic cell carcinomas have been reported in the English-language literature. We present the clinicopathologic features of four sinonasal acinic cell carcinomas.

METHODS

The demographic data and pathologic material of four patients with sinonasal acinic cell carcinoma identified from the files of the Department of Pathology at The University of Texas M. D. Anderson Cancer Center between 1984 and 2002 were reviewed.

RESULTS

The four patients were two men and two women, with an age range of 42 to 65 years (mean, 54 years). The patients were initially seen with unilateral nasal obstruction. Histologically, all tumors were composed of round to ovoid cells with clear and/or basophilic granular cytoplasm and round, hyperchromatic, small, eccentrically located nuclei. The growth pattern was lobular, solid, and follicular. Histochemically, periodic acid-Schiff diastase-resistant granules were demonstrated in all cases. All patients were treated surgically. In addition, one patient received postoperative radiation. All patients are alive and well, with follow-up from 4 to 17 years.

CONCLUSIONS

Sinonasal acinic cell carcinoma is a distinct low-grade carcinoma that can be distinguished from other neoplasms by light microscopy and histochemical staining methods. Pathologists and surgeons should be aware of the occurrence of this type of salivary gland neoplasm in the sinonasal tract.

Transglottic acinic cell carcinoma. Case report and literature review

Acinic cell carcinoma (ACC) is a rare tumor generally involving the parotid gland and infrequently the minor salivary glands with the potential for both local recurrence and metastatic spread when tracked for decades. The biological behavior of ACC cannot be predicted on the basis of histological features, and surgical stage is still the best predictor of clinical outcome. Only 5 cases of ACC of the larynx have been reported in the English literature. The authors present a case of a rare transglottic ACC in a 74-year-old woman. At admission, a submucosal mass involving the left arytenoid and adjacent aryepiglottic fold was noted. A CT scan of the head and neck region showed a mass of the left hemilarynx involving the paraglottic space and extending from the aryepiglottic fold to the sinus piriformis. Definitive histopathological examination showed an ACC with a large amount of clear cells. The patient was treated by radiotherapy alone (66 Gy in 7 weeks) with complete remission.

Malignant transformation of sialadenoma papilliferum of the palate: a case report

We report a case of a 79-year-old woman with an unusual salivary gland tumor that developed at the junction between the soft and hard palates. The tumor consisted of sialadenoma papilliferum (SP) with areas of an epithelial-myoepithelial carcinoma (EMC) component and a high-grade carcinoma component. There were also transitional regions among the SP, the EMC and the high-grade carcinoma components. The high-grade carcinoma component, which was similar to invasive micropapillary carcinoma of the breast, infiltrated into the right parapharyngeal space and metastasized to the lungs and cervical vertebrae. The high-grade carcinoma cells were positively immunostained for p53 protein. SP has been considered to be a benign tumor with exceptionally good prognosis, and, to the best of our knowledge, there has never been a confirmed case of malignant SP. This is the first report of SP with a definite malignant component.