A case of fine-needle aspiration of a neck mass with atypical squamous cells and macrophages.

Head and neck lesions often undergo fine-needle aspiration to determine the appropriate management and therapeutic decisions. However, there are numerous diagnostic challenges encountered with these specimens, particularly, if atypical squamous cells are identified. Here, we present a case of an enlarging right neck mass in a 38-year-old female and discuss the diagnostic difficulties and potential pitfalls. Additionally, we review the approach to diagnosis, including differential diagnostic considerations as well as available ancillary testing.

Large Solitary Lung Metastasis of a Matrix-Producing Metaplastic Breast Carcinoma: A Diagnostic Challenge.

Metaplastic breast carcinoma represents a diverse category of invasive breast cancers distinguished by the transformation of neoplastic epithelial cells into squamous cells or cells with mesenchymal appearance. Matrix-producing breast carcinoma is a variant of metaplastic breast carcinoma, an exceedingly uncommon malignancy accounting for less than 1% of all breast tumors. The precise origin of this tumor remains elusive; some molecular research points to a potential derivation from myoepithelial cells, while other studies emphasize the possibility of neoplastic transformation originating from multipotent stem cells. We report a case of recurrent matrix-producing breast carcinoma. The patient presented with a breast mass. The tumor cells displayed a lack of reactivity for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2), and exhibited a Ki-67 proliferation index of approximately 40%. Additionally, the tumor cells demonstrated significant reactivity for cytokeratins and S100. The patient underwent surgery, radiation, and chemotherapy and then developed metastasis to the lower lobe of her left lung, seven years after primary diagnosis. Diagnosis of metastasis was confirmed by comparing the metastasis to the primary tumor and staining with a panel of immunohistochemical stains. The patient is currently undergoing chemotherapy and immunotherapy.

Thoracic SMARCA4-deficient undifferentiated tumor with associated granulomatous reaction and response to pembrolizumab.

Thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT) is a rare entity that was recently described in the current World Health Organization Classification of Tumors. These lesions are highly aggressive with dismal prognosis, and most patients present with metastasis at the time of diagnosis. While there are about 100 cases of SMARCA4-UT described in the literature, there are only few existing reports that describe the cytomorphology of these lesions. We present a patient with masses involving the mediastinum, right lung, right supraclavicular lymph node and right adrenal gland. Subsequent core-needle biopsy of the right supraclavicular lymph node showed epithelioid to pleomorphic tumor cells with prominent nucleoli and associated granulomatous inflammation. The tumor cells were positive for CD34 and synaptophysin, and were negative for cytokeratins. SMARCA4 and SMARCA2 both showed loss of expression, which led to the diagnosis of SMARCA4-UT. The patient underwent treatment with pembrolizumab (PD-1 blocker), carboplatin, etoposide, and radiotherapy, resulting in an almost 55% reduction in the size of the primary tumor. Our case illustrates that an associated granulomatous inflammation might be an uncommon presentation of an already rare malignancy, and awareness of this phenomenon would prevent from mistaking SMARCA4-UT for other more well-known entities that can present with granulomas.

Metastatic malignant melanoma mimicking a salivary gland basaloid neoplasm after treatment with nivolumab.

Malignant melanoma is a well-known diagnostic pitfall, given its propensity to metastasize to different sites and mimic various entities. In this report, we present a fine-needle aspiration biopsy (FNA) of a metastatic melanoma with basaloid features that is occurring in the preauricular/parotid area. The patient is a 17-year-old male with a history of excision of melanoma of the left temple, and was undergoing adjuvant treatment with nivolumab. The prior excision was positive for S100, HMB-45, melan-A, and tyrosinase. On follow-up, he presented with non-FDG avid left preauricular area lesions. FNA was performed, and on-site evaluation demonstrated a cellular basaloid neoplasm with focal fibrillary stroma. Immunohistochemical stains revealed that the tumor cells were positive for SOX-10, S100, MITF, and HMGA2, and were negative for HMB-45, melan-A, tyrosinase, p63, cam 5.2 and PLAG1. The positive S100, SOX-10, and MITF results and negative cam 5.2 result supported the diagnosis of melanoma. Nivolumab was then stopped, Dabrafenib/Trametinib were started, and the patient underwent excision of the nodules. Nine-months later, he developed a rib metastasis that was positive for S100, SOX-10, melan-A, and tyrosinase. This report emphasizes that melanoma involving the parotid gland region has the potential to be misdiagnosed by FNA as a salivary gland neoplasm because of overlapping cytologic features and immunophenotypes. This pitfall is avoided by careful morphologic analysis and judicious use of ancillary studies.

Pulmonary carcinomas arising in association with scar: Cytomorphologic features in histologically confirmed cases.

BACKGROUND: Lung carcinoma arising in association with scar tissue is a well-reported but much debated phenomenon. Scar tissue complicates imaging and pathologic tumor measurement for cancer staging. To the best of our knowledge, the cytological findings in lung scar carcinoma (LSC) have not been described in the literature. Therefore, the aim of this study was to characterize the findings in fine-needle aspirations (FNA) from histologically confirmed LSCs. METHODS: LSCs were identified on retrospective search. Cases with preoperative FNA material were reviewed, including non-scar cases that were used for comparison. The clinical and histopathology findings were recorded. RESULTS: Twenty-seven cases associated with scar tissue had material for review and 35 cases not associated with scar tissue were used for comparison. The proportion of fibrosis in resection specimens ranged from 10% to 80%. Five (19%) FNA cases were hypocellular. There was no statistically significant difference between the scar and non-scar groups in terms of overall cellularity and diagnostic categories (P = .113 and P = .17, respectively). There was correlation between cytology and dominant pattern on histology in 19 (79%) adenocarcinoma cases. Spindle cells and fibrous or fibroelastotic fragments were present in 22 (81%) cases. CONCLUSION: This is the first study describing the cytology associated with LSCs. The presence of fibrosis did not adversely impact cellularity, which is likely due to multiple excursions and selective microdissection of tumor cells by the FNA needle. The cytomorphological and histological patterns correlated in most cases. FNA is able to provide a preoperative diagnosis of carcinoma despite the presence of fibrosis.

Application of the Milan System for Reporting Salivary Gland Cytopathology: Experience of an academic institution in a tertiary academic medical center.

BACKGROUND: The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) represents a standardized reporting system for salivary gland lesions. The recent literature has demonstrated a wide range of data regarding range of malignancy (ROM) and interobserver variability. The objective of the current study was to evaluate the reproducibility and interobserver agreement of MSRSGC, and establish the ROM in a unique patient population residing within a designated Health Professional Shortage Area. METHODS: A total of 380 salivary gland fine-needle aspiration cases were obtained over a 3-year period. Corresponding cytology reports and slides were reviewed in a blinded fashion by a panel of cytopathologists and recategorized using MSRSGC. ROM was calculated by cytohistologic correlation in 176 cases. Agreement between review of reports and slides and interobserver reliability were determined using kappa statistics. RESULTS: The ROMs per MSRSGC category based on review of reports and slides were as follows: 4% and 0%, respectively, for nonneoplastic; 22% and 0%, respectively, for nondiagnostic; 42.9% and 48%, respectively, for atypia of undetermined significance; 1.6% and 1.9%, respectively, for benign-neoplastic; 17.9% and 15.6%, respectively, for salivary gland neoplasm of uncertain malignant potential; 81.8% and 71.4%, respectively, for suspicious for malignancy; and 100% and 90.5%, respectively, for malignant. There was a 59.2% overall agreement between review of reports and slides with regard to recategorizing salivary gland lesions (kappa, 0.51). The interobserver reliability demonstrated a 64.6% agreement (weighted kappa, 0.59). CONCLUSIONS: The ROMs at the study institution appeared comparable to those in the published literature. There was moderate overall agreement among cytopathologists and low interobserver agreement with regard to the indeterminate categories. Image-guided fine-needle aspiration specimens; rapid onsite adequacy; and integration of clinical, imaging, and ancillary studies can improve diagnostic accuracy among indeterminate lesions.