Chondroid melanoma metastatic to lung and skin showing SOX-9 expression: a potential diagnostic pitfall

Melanoma cell plasticity poses diagnostic challenges: a case series

Phenotype switching is an emerging concept in melanoma research and deals with the cancer cell plasticity. In this paper, we present five cases of patients with metastatic malignant melanoma where the tumor underwent dramatic morphological and immunohistochemical changes thereby mimicking other types of malignancies. The diagnosis of melanoma in all these cases was based on the mutational profile of the tumor assessed by next-generation sequencing compared to the primary lesion or local regional lymph nodes. These cases highlight the importance of thorough diagnostic measures in patients with metastatic melanoma who show progressive disease and where basic pathological assessment shows a diagnostic discrepancy.

Melanoma with osseous or chondroid differentiation: a report of eight cases including SATB2 expression and mutation analysis

Melanoma can present with osteocartilaginous differentiation, however few reports exist on this rare subtype. We present eight cases of melanoma with osteocartilaginous differentiation to highlight its clinical, pathological and molecular features. The cases showed no association with gender (5 males and 3 females) or age (range 23-84 years). Cases included both primary melanomas and distant metastases (6 and 2, respectively), with the majority arising from cutaneous sites (7/8) and the remaining case from a mucosal site. Tumour-infiltrating lymphocyte (TIL) score ranged from 0 to 3 (median 1), and 2/8 lesions had evidence of inflammatory changes or antecedent trauma. No recurrent mutations were found in the tumours by next generation sequencing, and the mutations observed were typical of melanoma rather than osteosarcomatous lesions. The majority of tumours stained positive for melanoma markers including S100, HMB45, Melan-A, SOX10 and MITF. Staining of the osteoblastic marker SATB2 varied from negative to widespread positive. We demonstrate that melanomas with osteocartilaginous differentiation are heterogeneous in presentation and are not typified by a recurrent mutation in cancer associated genes. Where uncertainty exists in diagnosing an osteocartilaginous lesion, a diagnosis of melanoma can be supported by the presence of genomic mutations typical of melanoma such as BRAF, NRAS and NF1, and IHC staining positive for S100, HMB45, Melan-A, SOX10 and MITF. SATB2 may be positive in these lesions and thus should not be used to rule out melanoma.

BRAF-mutated malignant melanoma with chondrosarcomatous differentiation in inguinal nodal metastasis

We report the case of a young woman who developed metastatic melanoma in the inguinal nodal region, which acquired chondrosarcomatous differentiation and preserved the BRAF mutation found in the primary tumor. The patient was treated with a BRAF/MEK inhibitor combination therapy (dabrafenib/trametinib), which was demonstrated to be effective and well-tolerated.

NRAS Mutation Detected in a Melanoma With Chondroid Stroma: A Case Report With Molecular Evaluation and Literature Review of a Rare Form of Melanoma

Melanoma with cartilaginous differentiation is a rare histologic subtype that has been reported in the literature. It often presents clinically different than conventional melanomas and can be diagnostically challenging. Molecular alterations in previously reported cases have not been published. We present a case of melanoma with chondroid stroma from a 70-year-old man that was found to contain an NRAS mutation (c.182A>G (p.Q61R)) via Illumina TruSight Tumor 15 (TST15) next generation sequencing assay.

Chondroid atypical spitzoid melanocytic tumor

Chondroid stromal change is very rare in melanocytic nevi. We present a severely atypical symmetrical Spitz tumor on the right arm of a 24-years-old man. It showed maturation and occasional mitotic figures. The melanocytes were intermingled with cartilaginous stroma. The Ki67 proliferative rate was 5%. It was weakly positive for p16 and negative for BRAF/V600E. BAP1 expression was preserved. PCR for Myriad myPath^® Melanoma test was also negative.

Uncommon Histopathological Variants of Malignant Melanoma. Part 2

Despite new horizons opened by recent advances in molecular pathology, histological evaluation still remains the diagnostic gold standard regarding cutaneous melanocytic neoplasms. Several histological variants of melanoma have been described, and their knowledge is crucial for accurate diagnosis and classification of cases with unusual clinico-pathological features. Uncommon histological variants of melanoma have been described based on a broad constellation of features, including architectural pattern, stromal alterations, cytological attributes, and other morphological properties. This review is aimed at providing an extensive discussion of unusual but distinctive histopathological variants of melanoma.

Sarcomas of the Oral and Maxillofacial Region: Analysis of 26 Cases with Emphasis on Diagnostic Challenges

Sarcomas of the Oral and Maxillofacial Region (SOMR) are rare lesions which pose diagnostic and management challenges. We analyzed 26 cases of SOMR with respect to clinical presentation, histopathological subtype, treatment modalities, recurrence, and treatment outcome. In our series, Osteosarcoma (OS) was the most common type of sarcoma (7 cases), followed by 5 cases of Ewing's Sarcoma (ES), 3 cases each of Chondrosarcoma (CS) and Leiomyosarcoma (LMS), 2 cases each of Malignant Peripheral Nerve Sheath Tumor (MPNST), Pleomorphic Undifferentiated Sarcoma (PUS), Myeloid Sarcoma (MS)and Rhabdomyosarcoma (RMS). Surgery was the primary treatment modality in most cases and was combined with adjuvant chemo/ radiotherapy in few cases. 24 of the 26 cases were followed up for an average period of 40.67 months. Adverse disease outcomes like recurrence were seen in 2 cases whereas death due to the disease was reported in 7 cases. In view of the diagnostic challenges faced in SOMRs, it appears practical to stress on the underlying genetic aspects of the disease process rather than histological subtyping to improve disease outcome.

Malignant melanoma with osteosarcomatous differentiation in a lymph node metastasis

Osteocartilaginous differentiation in malignant melanoma is rare and can pose a diagnostic challenge. In previously reported cases, melanomas were predominantly located on acral and mucosal sites, with osteocartilaginous differentiation present in either primary or recurrent lesions. We report a case of a 52-year-old female with malignant melanoma located on the right upper back exhibiting osteosarcomatous differentiation only in the axillary lymph node metastasis. This case serves to highlight that the divergent differentiation can occur in lymph node metastases while being absent in the primary lesion. The patient's medical history, careful histological examination, and immunohistochemistry may be necessary for establishing the correct diagnosis.

Targeted alternative splicing of TAF4: a new strategy for cell reprogramming

Reprogramming of somatic cells has become a versatile tool for biomedical research and for regenerative medicine. In the current study, we show that manipulating alternative splicing (AS) is a highly potent strategy to produce cells for therapeutic applications. We demonstrate that silencing of hTAF4-TAFH activity of TAF4 converts human facial dermal fibroblasts to melanocyte-like (iMel) cells. iMel cells produce melanin and express microphthalmia-associated transcription factor (MITF) and its target genes at levels comparable to normal melanocytes. Reprogramming of melanoma cells by manipulation with hTAF4-TAFH activity upon TAFH RNAi enforces cell differentiation towards chondrogenic pathway, whereas ectoptic expression of TAF4 results in enhanced multipotency and neural crest-like features in melanoma cells. In both cell states, iMels and cancer cells, hTAF4-TAFH activity controls migration by supporting E- to N-cadherin switches. From our data, we conclude that targeted splicing of hTAF4-TAFH coordinates AS of other TFIID subunits, underscoring the role of TAF4 in synchronised changes of Pol II complex composition essential for efficient cellular reprogramming. Taken together, targeted AS of TAF4 provides a unique strategy for generation of iMels and recapitulating stages of melanoma progression.

SOX9, a potential tumor suppressor in cervical cancer, transactivates p21WAF1/CIP1 and suppresses cervical tumor growth

Sex-determining region Y-box 9 protein (SOX9) is a transcription factor that may act as both oncogene and tumor suppressor depending on tumor origin. Here we found that SOX9 expression was progressively decreased in cervical carcinoma in situ and especially in invasive cervical carcinoma, compared with normal cervix tissue. The effects of SOX9 on the proliferation, viability, and tumor formation of cervical carcinoma cells were assessed through the silencing and overexpression of SOX9. Overexpression of SOX9 in cervical carcinoma cells (SiHa and C33A) inhibited cell growth in vitro and tumor formation in vivo. In agreement, the silencing of SOX9 in HeLa cells promoted cell growth in culture and tumor formation in mice. Overexpression of SOX9 transactivated p21^WAF1/CIP1 via a specific promoter region, thus blocking G1/S transition. The quantitative chromatin immunoprecipitation analysis revealed physical interaction between SOX9 and the specific region of the p21^WAF1/CIP1 promoter. We suggest that SOX9 is a potential therapeutic target in cervical carcinoma, that specifically transactivates p21^WAF1/CIP1.

Sarcoma diagnosis in the age of molecular pathology

Mesenchymal neoplasia presents numerous challenges to pathologic classification. Histologic features can be deceiving, and traditional immunohistochemical markers of differentiation may be of little use in narrowing the diagnosis. Fortunately, great strides have been made in unraveling the genetic and genomic alterations associated with both sarcomagenesis and benign neoplasia. In turn, these advances have led to an expansion of the available diagnostic toolkit for sarcoma pathology. In order to assist the practicing pathologist in integrating these tools into their repertoire, this article will discuss some of the latest advances in sarcoma diagnosis, including an update on translocation-associated sarcomas, and will review a number of sarcoma-specific immunohistochemical studies developed over the past decade. Some of the potential uses and pitfalls of commonly used tests will be addressed. Finally, the discussion will briefly touch upon the impact that advances in molecular technologies, particularly targeted gene expression analysis, may have on altering the face of diagnostic pathology.