SATB2 and MDM2 Immunoexpression and Diagnostic Role in Primary Osteosarcomas of the Jaw

Primary osteosarcomas of the jaw (OSJ) are rare, accounting for 6% of all osteosarcomas. This study aims to determine the value of SATB2 and MDM2 immunohistochemistry (IHC) in differentiating OSJ from other jawbone mimickers, such as benign fibro-osseous lesions (BFOLs) of the jaw or Ewing sarcoma of the jaw. Certain subsets of osteosarcoma harbor a supernumerary ring and/or giant marker chromosomes with amplification of the 12q13–15 region, including the murine double-minute type 2 (MDM2) and cyclin-dependent kinase 4 (CDK4) genes. Special AT-rich sequence-binding protein 2 (SATB2) is an immunophenotypic marker for osteoblastic differentiation. Cases of OSJ, BFOLs (ossifying fibroma and fibrous dysplasia) of the jaw, and Ewing sarcoma of the jaw were retrieved from the Departments of Oral Pathology and Oral Medicine, Faculty of Dentistry, Obafemi Awolowo University and Lagos State University College of Medicine, Nigeria. All OSJ retrieved showed histologic features of high-grade osteosarcoma. IHC for SATB2 (clone EP281) and MDM2 (clone IF2), as well as fluorescence in situ hybridization (FISH) for MDM2 amplification, were performed on all cases. SATB2 was expressed in a strong intensity and diffuse staining pattern in all cases (11 OSJ, including a small-cell variant, 7 ossifying fibromas, and 5 fibrous dysplasias) except in Ewing sarcoma, where it was negative in neoplastic cells. MDM2 was expressed in a weak to moderate intensity and scattered focal to limited diffuse staining pattern in 27% (3/11) of cases of OSJ and negative in all BFOLs and the Ewing sarcoma. MDM2 amplification was negative by FISH in interpretable cases. In conclusion, the three cases of high-grade OSJs that expressed MDM2 may have undergone transformation from a low-grade osteosarcoma (LGOS). SATB2 is not a dependable diagnostic marker to differentiate OSJ from BFOLs of the jaw; however, it could serve as a valuable diagnostic marker in differentiating the small-cell variant of OSJ from Ewing sarcoma of the jaw, while MDM2 may be a useful diagnostic marker in differentiating OSJ from BFOLs of the jaw, especially in the case of an LGOS or high-grade transformed osteosarcoma.

Spindle cell variant of medullary thyroid carcinoma: a clinicopathologic study of four cases

Background Medullary thyroid carcinoma (MTC) is a malignant tumor derived from C cells. It accounts for about 10% of all thyroid malignancies. More than 14 histological variants have been described. Among them, spindle cell variant is extremely rare. Case presentation Here we describe 4 cases of spindle cell variant of MTC collected from 2012 to 2019. Ultrasound showed solid and hypoechoic nodules. Three patients underwent total thyroidectomy and regional lymph node dissection, and 1 patient underwent thyroid mass resection. Histologically, the tumors showed spindle shaped cells in bundles or interlaced arrangement, separated by hyalinised fibrous stroma that contained amyloid deposits. Immunohistochemistry showed that the tumor cells were positive for calcitonin, chromogranin A, synaptophysin, CD56, and TTF-1, but negative for other lineage-specific markers. Conclusions We report 4 rare cases of spindle cell variant of MTC. Due to its rarity and special morphology, the diagnosis of spindle cell variant MTC relies on its morphology and immunohistochemical markers to avoid misdiagnosis.

Elucidating the Characteristics of Two Tumor Cell Populations in Small Cell Variant of Anaplastic Lymphoma Kinase-Positive Anaplastic Large Cell Lymphoma

The small cell variant of anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (SC-ALCL) is a subtype defined as comprising two distinct tumor cell populations in immunohistochemistry: small cells staining negative or weakly positive for ALK and CD30 protein; and large cells staining strongly positive for those proteins. Although the constitution of these two different cell populations might contribute to the poor prognosis, detailed characterization of each population by molecular-based approaches has not been done due to the difficulty of cell separation from solid tumor sample. In this paper, we have analyzed the characterization of each tumor cell population using the patient sample from SC-ALCL leukemic phase obtained from peripheral blood by molecular-based approaches. Flow cytometric analysis revealed two distinct abnormal populations. The major population comprising 74% of total leukocytes was positive for CD3 and CD8, and negative for CD4, CD5, CD25 and CD30. The minor population comprising 5% of total leukocytes was positive for CD25, CD30, CD11b and CD13. Fluorescent in situ hybridization with ALK break-apart probes and RT-PCR analysis confirmed that most of the cells including both populations were rearranged with NPM-ALK gene. To elucidate the cause underlying the distinct levels of ALK protein expression in each population, we separated those tumor cells by CD30-PE antibody and a magnetic bead separation kit, extracted DNA and RNA from each population, and compared NPM-ALK mRNA expression levels by droplet digital polymerase chain reaction. The expression level of NPM-ALK mRNA in the CD30-negative population was ten-fold less than that in the CD30-positive population (Table). This result indicated that the two tumor cell populations expressed the distinct level of NPM-ALK mRNA, although both populations possessed NPM-ALK fusion gene. To assess the effectiveness of various chemotherapies in each tumor cell population, we monitored each population in peripheral blood by flow cytometric analysis (small cell; CD30-5-8+, large cell; CD30+) over time. Intriguingly, CD30-negative population behaved as chemo-resistant cells in clinical course, however alectinib, a second-generation ALK-inhibitor, eradicated both populations inducing first complete remission. This study revealed two definitive features regarding the small CD30-negative population of SC-ALCL, with a lower expression level of NPM-ALK mRNA transcripts and chemoresistance. The cause of distinct ALK staining levels in immunohistochemistry was revealed depending on the distinct expression level of NPM-ALK mRNA transcripts. Finally, since both populations were sensitive to ALK-inhibitor, early administration of ALK-inhibitor might be the reasonable option for SC-ALCL. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Targeted Therapy of Papillary Thyroid Cancer: A Comprehensive Genomic Analysis

BackgroundA limited number of targeted therapy options exist for papillary thyroid cancer (PTC) to date. Based on genetic alterations reported by the “The Cancer Genome Atlas (TCGA)”, we explored whether PTC shows alterations that may be targetable by drugs approved by the FDA for other solid cancers.MethodsDatabases of the National Cancer Institute and MyCancerGenome were screened to identify FDA-approved drugs for targeted therapy. Target genes were identified using Drugbank. Genetic alterations were classified into conferring drug sensitivity or resistance using MyCancerGenome, CiViC, TARGET, and OncoKB. Genomic data for PTC were extracted from TCGA and mined for alterations predicting drug response.ResultsA total of 129 FDA-approved drugs with 128 targetable genes were identified. One hundred ninety-six (70%) of 282 classic, 21 (25%) of 84 follicular, and all 30 tall-cell variant PTCs harbored druggable alterations: 259 occurred in 29, 39 in 19, and 31 in 2 targetable genes, respectively. The BRAF V600 mutation was seen in 68% of classic, 16% of follicular variant, and 93% of tall-cell variant PTCs. The RET gene fusion was seen in 8% of classic PTCs, NTRK1 and 3 gene fusions in 3%, and other alterations in <2% of classic variant PTCs. Ninety-nine of 128 (77%) FDA-approved targetable genes did not show any genetic alteration in PTC. Beside selective and non-selective BRAF-inhibitors, no other FDA-approved drug showed any frequent predicted drug sensitivity (<10%).ConclusionTreatment strategies need to focus on resistance mechanisms to BRAF inhibition and on genetic alteration–independent alternatives rather than on current targeted drugs.

METAPLASTIC CARCINOMA OF BREAST : A CASE REPORT

Metaplastic breast cancer constitute nearly 1 % of all breast carcinoma cases. There is metaplasia of normal epithelial components of the breast into other types. They are highly aggressive with very poor prognosis. Here we present a case of 30 year old female who presented with a breast lump in her left breast associated with dull aching pain. It was 10 x 10 cm in size involving upper inner, upper outer, lower outer quadrants and retroareolar area of left breast. USG was suugestive of BIRADS VI lesion. Axillary lymph nodes were not found enlarged clinically or radiologically. Core biopsy report showed Phylloides tumor of breast. The patient underwent simple mastectomy of left breast and histopathology revealed spindle cell variant of metaplastic breast cancer. The cell blocks sent for immunohistochemistry were negative for estrogen, progesterone receptors and Her2neu receptor. The post surgical treatment of this type of breast cancer is still under study.

Unusual endophytic non-enhancing tumour in the renal pelvis: a diagnostic dilemma

Renal cell cancer (RCC) is incidentally detected on imaging in 50%–60% of cases. Among the RCCs, clear cell variant is most common and classically seen as heterogenous enhancing lesion on CT imaging. Hypoenhancing mass presents a diagnostic dilemma with differential diagnosis being urothelial carcinoma, fat poor angiomyolipoma, oncocytoma or rarer variants of RCC. Such cases require further evaluation in form of urine cytology or newer molecular diagnostic techniques. Here, we present a case of renal mass with minimal enhancement on CT scan and imaging features suggestive of upper tract urothelial cancer. Final histopathology revealed the mass to be chromophobe variant of renal cell carcinoma.