The role of next-generation sequencing in the differential diagnosis of composite neoplasms

Cytologic Diagnoses of Lung Adenocarcinoma With Concomitant Metastasis From a Different Primary: A Case Series

Lung adenocarcinoma is a common malignancy that can metastasize. The lung is also a common site for metastasis from other sites. Prompt and accurate diagnosis is critical for patient management. The diagnosis of lung adenocarcinoma can be occasionally challenging due to overlapping clinical and pathological features with adenocarcinomas from other origins. We present three cases of lung adenocarcinomas with concomitant metastatic adenocarcinomas of different primaries in the same endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA) or core biopsy procedures. The first case showed metastatic ROS-rearranged lung adenocarcinoma and metastatic ampullary adenocarcinoma involving different mediastinal lymph nodes, respectively, in a patient with no previous history of malignancy. The second case showed metastatic lung adenocarcinoma with MET exon 14 deletion and metastatic breast adenocarcinoma involving different mediastinal lymph nodes, respectively, in a patient with a previous history of breast carcinoma. The third case showed metastatic prostatic adenocarcinoma to a pre-existing lung mucinous adenocarcinoma in a patient with a previous history of prostatic adenocarcinoma. Our report highlights attention to details, judicious use of immunostains, and ancillary molecular studies in complex pathology cases. Cytohistological findings are also correlated with molecular test results.

Occult collision tumor of the gastroesophageal junction comprising adenocarcinomas with distinct molecular profiles

Collision tumors, characterized by the coexistence of two unique neoplasms in close approximation, are rare and pose diagnostic challenges. This is particularly true when the unique neoplasms are of the same histologic type. Here we report such a case where comprehensive tumor profiling by next generation sequencing (NGS) as well as immunohistochemistry revealed two independent adenocarcinomas comprising what was initially diagnosed as a single adenocarcinoma of the gastroesophageal (GEJ) junction. Biopsy of the esophageal portion of the GEJ mass showed a mismatch repair deficient tumor with loss of immunoreactivity for MLH1 and PMS2, while the biopsy taken from the gastric portion of the mass revealed a separate tumor with a discordant, non-overlapping, set of molecular alterations, including an EML4::ALK fusion, as well as intact MMR. This case illustrates one way in which NGS can reveal diagnoses such as collision tumor that are wholly unexpected based on clinical and histological grounds. Such diagnoses can have important implications for patient care, particularly in cases where there is discordance for targetable molecular alterations.

Tumor-to-tumor metastases: systematic review and meta-analysis of 685 reported cases

Tumor-to-tumor metastasis is an exceedingly rare phenomenon where secondary deposits of a tumor develops in another one. Our systematic review and meta-analysis aims to uncover and analyze reported cases to enhance our understanding and improve patients' care. A comprehensive search of the literature was conducted to identify 685 cases of tumor-to-tumor metastasis from 543 articles. Key information, including the donor and recipient organs, tumor histology, primary to metastasis time interval, presence of distant metastases and overall survival was extracted and analyzed. The highest incidence of tumor-to-tumor metastasis was observed in breast cancer and lung cancer metastasizing to meningioma (n = 52, 7.6%; n = 49, 6.2%; respectively). There were 131 (19.2%) autopsy cases, 477 (69.6%) cases diagnosed in vivo, and in 77 cases (11.2%), the timing of diagnosis was unavailable. Death of the patient (including autopsy cases) was reported in 256 (37.4%) cases. In 160 (23.35%) patients, the primary of the metastasis (POM) was occult at the time of metastasis, and in 385 (56.2%) cases, the POM was already known. The median period between clinically overt primary cancer diagnosis and tumor-to-tumor metastasis was 2.0 years. Donor metastases to other sites were observed in 328 (47.9%) cases. In multivariate Cox regression analysis, the primary-to-metastasis interval (< 3 vs > 3 years, HR 2.01, 95% CI 1.18-3.43, p = 0.01) and the presence of donor metastases to other sites (present vs absent; HR 0.37, 95% CI 0.23-0.59, p < 0.001) were significantly associated with survival. In summary, our findings emphasize the necessity for heightened clinical vigilance, early detection, and tailored management to effectively address this unique and challenging clinical scenario.

Mutually exclusive driver mutations identifies 2 separate primaries in a collision tumor initially interpreted as a solitary lung adenocarcinoma with tumor heterogeneity

Distinction of histologically heterogenous, single primary tumor from two or more collision tumors with different primaries could represent a challenge to practicing pathologists. Histologic variations including differences in degree of differentiating within a tumor, are typically interpreted as tumor heterogeneity in a contiguous small size tumor biopsy. The authors report a case of adult former smoker female who presented with lung mass and a metastatic lytic lesion of acetabulum. A needle biopsy of a lung mass revealed an adenocarcinoma with well and moderately differentiated components. Next generation sequencing studies proved 2 different primaries in this small needle biopsy.

In-Depth Comparison of Genetic Variants Demonstrates a Close Relationship Between Invasive and Intraductal Components of Prostate Cancer

Intraductal carcinoma (IDC) of the prostate is often associated with concurrent high-grade invasive prostate cancer (PCa) and poor clinical outcomes. In this context, IDC is thought to represent the retrograde spread of invasive prostatic adenocarcinoma into the acini and ducts. Prior studies have demonstrated a concordance of PTEN loss and genomic instability between the IDC and high-grade invasive components of PCa, but larger genomic association studies to solidify our understanding of the relationship between these 2 lesions are lacking. Here, we evaluate the genomic relationship between duct-confined (high-grade prostatic intraepithelial neoplasia and IDC) and invasive components of high-grade PCa using genetic variants generated by whole exome sequencing. High-grade prostatic intraepithelial neoplasia and IDC were laser-microdissected, and PCa and nonneoplastic tissue was manually dissected from 12 radical prostatectomies. A targeted next-generation sequencing panel was used to identify disease-relevant variants. Additionally, the degree of overlap between adjacent lesions was determined by comparing exome-wide variants detected using whole exome sequencing data. Our results demonstrate that IDC and invasive high-grade PCa components show common genetic variants and copy number alterations. Hierarchical clustering of genome-wide variants suggests that in these tumors, IDC is more closely related to the high-grade invasive components of the tumor compared with high-grade prostatic intraepithelial neoplasia. In conclusion, this study reinforces the concept that, in the context of high-grade PCa, IDC likely represents a late event associated with tumor progression.

Utilization of cytologic cell blocks for targeted sequencing of solid tumors

BACKGROUND

Targeted sequencing of cytologic samples has significantly increased in recent years. With increasing numbers of clinical trials for variant specific therapeutics, validating a comprehensive assay for cytologic samples has become clinically important.

AIM

For this study, a retrospective review of cytologic cell blocks from fine needle aspirations and fluid specimens was performed.

METHODS

Two hundred twenty six total cases of solid tumor malignancies were identified, of which 120 cases and 20 lymph node negative controls were sequenced for the Oncomine Comprehensive Assay. Cytology and surgical specimen correlation was performed in a subset of cases. Statistical analysis to determine variant concordance was performed.

RESULTS

Within the 117 cases sequenced, a total of 347 pathogenic variants were detected. Of the 117 cases, 32 cases (27.4%) would qualify for FDA approved targeted therapy according to the current guidelines, and an additional 23 cases (19.7%) would qualify for clinical trial based on pathogenic variants detected.

DISCUSSION

With over 27% of cases in our cohort qualifying for some form of targeted therapy, our study shows the importance of providing comprehensive molecular diagnostic options. Despite only half of the cytology cases in the review period having enough material to be sequenced, overall approximately 27% of patients in this cohort would have benefitted from this service.

Adrenal pheochromocytoma: is it all or the tip of the iceberg?

Adrenal pheochromocytoma is not always a simple retroperitoneal tumor but may be part of a more complicated condition. It often has a spectrum of complex and variable imaging features, may present as a collision tumor and composite tumor, and is associated with a variety of clinical syndromes. A comprehensive understanding of the clinical, pathological, and variable imaging manifestations of pheochromocytoma can help radiologists make an accurate diagnosis. This article reviews various special imaging features of pheochromocytoma and pheochromocytoma-related diseases.

Malignant carcinoma and skin melanoma neoplasms concomitantly in the thyroid

Malignant melanomas metastatic to the thyroid gland are uncommon. Based on microscopy and DNA methylation profile, we report a rare coexistence of neoplasms in the thyroid, presumably in our case, with relapse-free condition on adjuvant therapy.

Next generation sequencing of cervical high grade dysplasia and invasive squamous cell carcinoma: A case study

Cervical cancer continues to be a prevalent diagnosis among gynecologic pathology despite widespread screening methods and known pathogenesis by human papilloma virus. We describe a patient who underwent next generation sequencing (NGS) of her high grade squamous dysplasia (HG-SIL) as well as the invasive component of her cervical cancer. This tumor showed an amplification of PIK3CA in the invasive carcinoma in addition to a common E542K mutation both in dysplastic and invasive carcinoma. The dysplasia also showed a novel PCNX (e1) - RAD51B (e8) fusion suggesting potentially new mechanisms of pathogenesis in cervical squamous cell carcinoma.