Complex neurological paraneoplastic syndrome in lung cancer with myastheniform syndrome and mononeuritis multiplex
Pedro J Modrego*, Leyre Diaz de Cerio.
Department of Neurology, Hospital Universitario Miguel Servet, Zaragoza, Spain
*Corresponding author
*Pedro J Modrego, Department of Neurology, Hospital Universitario Miguel Servet, Zaragoza, Spain.
DOI: 10.55920/JCRMHS.2024.07.001293
Figure 1: Chest X ray: diffuse interstitial pattern.
Figure 2: CMAP potentials decreased in both arms in an asymmetric way. Ulnar nerves (A and B), median nerves (C and D). The values are normal in the legs: tibial nerves (E and F), and peroneal nerves (G and H).
Figure 3: CT of the chest; nodule of 19 mm in the posterior region of the left.
The symptoms did not improve with piridostigmine and prednisone at doses of 1 mg/kg weight. With all data we retained the diagnosis of paraneoplastic myastheniform syndrome (not fulfilling criteria of Lambert-Eaton syndrome), and mononeuritis multiplex of paraneoplastic nature. Then, the patient underwent a Chest-CT revealed a pulmonary nodule of 19 mm with malignant aspect in the left inferior lobe (Figure 3), with a left paratracheal enlarged lymph node. PET-scan confirmed malignancy of the nodule and the malignant lymph node. Complete resection of the left inferior pulmonary and 5 lymph nodes lobe was performed with favorable outcome. The biopsy showed an adenocarcinoma with a molecular profile negative for the mutations EGFR, BRAF, ALK and ROS-1, PDL-1 lower than 1%. Only one lymph node showed malignancy, After surgery, four cycles of cisplatin plus pembrolizumab were administered, with tolerable side-effects (fatigue). Two months after surgery, the patient developed weakness and asymmetric atrophy of the intrinsic muscles of the hands predominantly in the left hand and interosseous muscles. The ophthalmological symptoms improved remarkably with 3-4-diaminopirydine, ptosis resolved in two weeks, but ocular motility took one year toresolve. Diaminopiridine was tapered. Sensory and motor symptoms in the face and arms improved after surgical resection, but some residual symptoms remain after two-year follow-up period.



