Tata Steel (India)

Spindle cell malignancies of the oral cavity are uncommon and pose considerable diagnostic challenges due to overlapping histomorphology and immunohistochemical features. Malignant peripheral nerve sheath tumor (MPNST) with heterologous differentiation is particularly rare. Moreover, its coexistence with a synchronous hematological malignancy such as small cell lymphoma (SLL) is exceedingly unusual. A male 62 year, presented with a progressively enlarging, pigmented, ulcero-proliferative painless mass over the right upper alveolus extending to the hard palate. Imaging revealed a heterogeneously enhancing mass with cervical lymphadenopathy. Initial punch biopsy suggested fibroma/low-grade spindle cell neoplasm, but frozen biopsy raised the suspicion of malignant melanoma or spindle cell sarcoma. The patient underwent right upper alveolectomy with bilateral modified radical neck nodal dissection (MRND). Histopathological evaluation revealed spindle cell morphology with heterologous melanin pigmentation, favoring MPNST with dedifferentiation. Extensive nodal dissection (134 lymph nodes) revealed small cell lymphoma (SLL, stage I) in a few nodes. Immunohistochemistry (IHC) confirmed a dual primary malignancy -MPNST with rhabdomyoblastic and smooth muscle differentiation coexisting with SLL. This case illustrates the uniqueness of synchronous dual malignancies involving MPNST and SLL, a combination rarely documented in the oral cavity. The diagnostic challenge lay in distinguishing spindle cell malignancies with overlapping features, requiring multidisciplinary approach and IHC testing. The patient was managed with complete surgical excision and adjuvant radiotherapy (60Gy/30 Fractions), with no evidence of systemic lymphoma or metastasis. for six weeks. At two yrs follow up, the patient remained disease free, highlighting the favorable outcome despite the complexity of diagnosis.

High-temperature material lifespan depends on the structural property aspects of the base metals, especially the weld zone metallurgy. In order to achieve the high-temperature properties and to avoid degradation, it is necessary to understand the welding metallurgy of the material. In this research, Nimonic-263, a nickel-based superalloy, is used as the base metal. Nimonic-263 plates with a thickness of 5 mm are butt welded together using electron beam welding. A detailed weld zone microstructure was analysed using an optical and field emission scanning electron microscope. An elemental analysis performed on the fusion zone revealed that the beam welding had produced a very little microsegregation without altering the composition of the fusion zone. An XRD analysis showed that there are no deleterious precipitates formed during the welding process. The residual stress of the weld zone is measured by a cos α method. A compressive residual stress was observed in the root and section weld of −204 MPa and tensile residual stress of 343 MPa in the cap section, respectively. The welded specimen has a yield strength, ultimate strength and maximum elongation of 326.06 MPa, 802.56 MPa and 54.92%. The detailed structure–property aspects of the electron beam-welded Nimonic-263 are represented in this article.