Paraneoplastic Syndromes in Lung Cancers: Manifestations of Ectopic Endocrinological Syndromes and Neurologic Syndromes

Myasthenia-like paraneoplastic syndrome with multiple cranial nerve tumor infiltration: A case report and literature review

RATIONALE

Approximately 0.001% of patients with cancer have paraneoplastic nerve system syndrome, which can affect the central nervous system, neuromuscular junction, or peripheral nervous system. Although myasthenia gravis (MG) may exist as a thymic paraneoplastic syndrome (PNPS), its association with primary lung cancer remains unknown.

PATIENT CONCERNS

A 55-year-old female presented with slurred speech, weakness in chewing, sporadic difficulty in swallowing, and weakness in both lower limbs for half a year.

DIAGNOSES

Based on cerebrospinal fluid and electromyography findings, we present the case of a female patient diagnosed with overlapping multicranial nerve tumor infiltration and MG-like neurological PNPS secondary to lung adenocarcinoma.

INTERVENTIONS

The patient received intrathecal injections of pemetrexed and neurotrophic (vitamin B) therapy before ceasing chemoradiotherapy and chose cabozantinib on her own.

OUTCOMES

Weakness of the proximal limbs, choking cough, and chewing problems did not improve significantly.

LESSONS

Although it is unclear why MG coexists with lung cancer, it is probable that MG is a paraneoplastic condition. Cerebrospinal fluid testing should be carried out along with electrophysiological, serological, and pharmacological procedures pertinent to the diagnosis of MG to thoroughly examine if people simultaneously experience MG-like PNPS and tumor growth. Starting immunotherapy and anticancer medication at the same time that tumor development and MG-like syndrome are discovered is crucial.

Immunohistochemical Profile of Parathyroid Tumours: A Comprehensive Review

Immunohistochemistry remains an indispensable tool in diagnostic surgical pathology. In parathyroid tumours, it has four main applications: to detect (1) loss of parafibromin; (2) other manifestations of an aberrant immunophenotype hinting towards carcinoma; (3) histogenesis of a neck mass and (4) pathogenetic events, including features of tumour microenvironment and immune landscape. Parafibromin stain is mandatory to identify the new entity of parafibromin-deficient parathyroid neoplasm, defined in the WHO classification (2022). Loss of parafibromin indicates a greater probability of malignant course and should trigger the search for inherited or somatic CDC73 mutations. Aberrant immunophenotype is characterised by a set of markers that are lost (parafibromin), down-regulated (e.g., APC protein, p27 protein, calcium-sensing receptor) or up-regulated (e.g., proliferation activity by Ki-67 exceeding 5%) in parathyroid carcinoma compared to benign parathyroid disease. Aberrant immunophenotype is not the final proof of malignancy but should prompt the search for the definitive criteria for carcinoma. Histogenetic studies can be necessary for differential diagnosis between thyroid vs. parathyroid origin of cervical or intrathyroidal mass; detection of parathyroid hormone (PTH), chromogranin A, TTF-1, calcitonin or CD56 can be helpful. Finally, immunohistochemistry is useful in pathogenetic studies due to its ability to highlight both the presence and the tissue location of certain proteins. The main markers and challenges (technological variations, heterogeneity) are discussed here in the light of the current WHO classification (2022) of parathyroid tumours.

Case Report: Hematologic Recovery Following Stereotactic Ablative Radiotherapy in a Patient With Early-Stage Non-Small Cell Lung Cancer and Paraneoplastic Myelofibrosis

Herein, we report the first case presentation of paraneoplastic myelofibrosis associated with cancer. Paraneoplastic syndromes occur in some patients with thoracic malignancies; however, myelofibrosis is not commonly seen in non-small cell lung cancer (NSCLC). We report a case of myelofibrosis in a patient with a new diagnosis of NSCLC that resolved after stereotactic ablative radiotherapy (SABR). In conclusion, NSCLC may evoke unexpected systemic effects that resolve with treatment.