Thymoma, commonly seen in middle-aged and elderly individuals, is associated with autoimmune disorders. While renal involvement is rare, its occurrence remains poorly characterized. We report a 24-year-old female with a ten-year history of malignant thymoma who developed nephrotic syndrome. Renal biopsy revealed minimal change disease (MCD), a rare paraneoplastic manifestation of thymoma. Despite treatment with steroids and rituximab, her renal function deteriorated, leading to end-stage renal disease (ESRD). This case underscores the challenges of managing paraneoplastic glomerular disease and highlights the need for better understanding of such rare associations. Thymoma-related glomerular diseases, often linked to immune dysregulation, pose significant treatment challenges. Recognizing these associations may guide more effective management strategies, particularly for patients unresponsive to steroids.

Atypical thymomas are a rare form of primary thymic epithelial neoplasm that are characterized by conservation of most of the organotypical features of thymic differentiation, but show atypical cytological features. The spectrum of histologic features and growth patterns these tumors can exhibit have not been extensively documented or illustrated in the literature. The basic histologic growth patterns seen in atypical thymomas include the epithelioid or "Squamoid" subtype and the spindle cell subtype. The histologic picture may often be confused with thymic carcinomas or metastatic disease, in particular squamous cell carcinoma due to the overlap in histologic features. In addition, these subtypes may be seen in combination with each other or in combination with conventional types of thymoma including type A, type AB, type B1 and type B2. Cases of thymic carcinoma arising from atypical thymoma have also been documented in the literature. The biologic behavior of atypical thymomas is intermediate between conventional thymoma and thymic carcinoma. The tumors tend to present with aggressive behavior and an increased rate of metastasis and thus achieving the correct diagnosis is of utmost importance. We present a review of the various morphologic appearances of these tumors to emphasize the wide spectrum of histologic features that they can display, with a discussion of the current nomenclature and approach to these neoplasms.

Jahnavi Gandhi, DCPObjective  Pathological diagnosis of thymic epithelial neoplasms is challenging due to multiple subtypes, tumor heterogeneity, and variations in inter-observer reproducibility. Very few studies are available on their spectrum in the Indian subcontinent. In this study, we aimed to explore the morphological spectrum and diagnostic difficulties in the classification and subtyping of thymic epithelial neoplasms along with their prognostic significance in the Indian population. Material and Methods  Retrospectively, all surgically resected thymectomy specimens operated at our institute as well as outside review cases during the period were included. Histomorphology and immunohistochemistry (IHC) slides were reviewed and correlated with clinicopathological variables. Statistical Analysis  Microsoft Excel 2019 and SPSS version 20 were used for data analysis. Results  Among the 33 thymic epithelial neoplasms operated during the study period, the commonest subtype was thymoma B2 type followed by AB, B1, A, and B3 types. A single case each of micronodular thymoma, microscopic thymoma, and thymic carcinoma were identified. Six cases of thymomas with more than one pattern (other than 'A') were noted. The male:female ratio was 2:1. Stage I in Modified Masaoka staging and pT1a in TNM staging were most common. Seven cases had metastasis, four during initial presentation and three during subsequent follow-up. Discussion and Conclusion  Thymic epithelial neoplasms show morphological overlapping of features. Thorough sampling, morphology, and IHC for exact subtyping of thymoma and diligent search and documenting of lymphovascular invasion (LVI) are vital as both are separate risk factors for metastasis/recurrence and help the clinician in a better follow-up of patients.

Thymic epithelial tumors (TET) are rare malignancies and lack well-defined biomarkers for neoadjuvant therapy. This study aimed to evaluate the clinical utility of artificial intelligence (AI)-powered tumor-infiltrating lymphocyte (TIL) analysis in TET. Patients initially diagnosed with unresectable thymoma or thymic carcinoma who underwent neoadjuvant therapy between January 2004 and December 2021 formed our study population. Hematoxylin and eosin-stained sections from the initial biopsy and surgery were analyzed using an AI-powered spatial TIL analyzer. Intratumoral TIL (iTIL) and stromal TIL (sTIL) were quantified and their immune phenotype (IP) was identified. Thirty-five patients were included in this study. The proportion of patients with partial response to neoadjuvant therapy was higher in the group with nondesert IP in preneoadjuvant biopsy (63.6% vs. 17.6%, p = 0.038). A significant increase in both iTIL (median 22.18/mm2 vs. 340.69/mm2 , p < 0.001) and sTIL (median 175.19/mm2 vs. 531.02/mm2 , p = 0.004) was observed after neoadjuvant therapy. Patients with higher iTIL (>147/mm2 ) exhibited longer disease-free survival (median, 29 months vs. 12 months, p = 0.009) and overall survival (OS) (median, 62 months vs. 45 months, p = 0.002). Patients with higher sTIL (>232.1/mm2 ) exhibited longer OS (median 62 months vs. 30 months, p = 0.021). Nondesert IP in initial biopsy was associated with a better response to neoadjuvant therapy. Increased infiltration of both iTIL and sTIL in surgical specimens were associated with longer OS in patients with TET who underwent resection followed by neoadjuvant therapy.

The most common thymic tumours, thymomas, are derived from thymic epithelium and are generally low-grade neoplasm. Frankly malignant tumours, thymic carcinomas are rarer still. Exceedingly rare thymic tumours contain a mesenchymal tissue component such as fibrous connective tissue and/or mature fat. Lipofibroadenoma (LFA) is a very rare mixed epithelial-mesenchymal thymic tumour, included in the category of thymic epithelial tumors. LFA in addition to a mature adipocytic component, contains variable epithelial and mesenchymal tissue components. Owing to the presence of an epithelial component in LFA, this entity, in contrast to thymolipoma, is included in the World Health Organization (WHO) category of thymic epithelial neoplasm. Currently only 12 LFA cases have been described. The 12 previously reported cases all behaved in a benign fashion, although four cases were associated with a conventional type of thymoma. We here present a new, 13th, case of LFA. The LFA was discovered incidentally in a previously healthy 17-year-old male after investigations for suspected pneumonia. On imaging a mass was discovered in the anterior mediastinum which was subsequently surgically removed. The resected tumour was extensively investigated, including the first instance of full molecular analysis of this rare entity and all available literature on LFA was sourced to provide a comprehensive overview. The histology of this LFA was similar to previously described cases. No gene mutations or rearrangements were identified. The patient made an uneventful recovery and after 13 months of follow-up remained well. An additional, 13th case of LFA is presented. Based on the available literature it appears that LFA may be considered a benign composite thymic tumour, although the combination of an additional conventional thymoma component may warrant closer follow-up.