Myasthenia Gravis Complicated with Peripheral T-cell Lymphoma, Not Otherwise Specified (PTCL-NOS), Following Thymectomy and Longstanding Tacrolimus Therapy

Cancer in myasthenia gravis subtypes in relation to immunosuppressive treatment and acetylcholine receptor antibodies: A Swedish nationwide register study

BACKGROUND AND PURPOSE

The potentially increased risk of extrathymic cancers in myasthenia gravis (MG) remains uncertain. We present the occurrence of extrathymic cancer diagnoses in different MG subgroups.

METHODS

We conducted a nationwide Swedish register-based cohort study, including patients who had their first MG diagnosis or first prescription of acetylcholine esterase inhibitors between the years 2006 and 2018. Timing and subtypes of cancer diagnosis in relation to MG as well as corticosteroid-sparing immunosuppressants (CSISs) were identified from national patient, cancer and drug registers.

RESULTS

In the study population of 2812 MG patients, 92 had juvenile MG (3%), 632 had early-onset MG (23%), 1968 had late-onset MG (LOMG; 70%) and 120 patients had thymoma-associated MG (TAMG; 4%). Extrathymic cancers were observed in 630 patients (22.4%). Skin cancer and cancer in the male genital organs were most common (N = 138, respectively), followed by cancers in the female genital organs (N = 103), digestive organs (N = 90) and breast (N = 80). Patients with TAMG (29.2%) and LOMG (28.4%) had the highest occurrence of extrathymic cancer. Cancer frequency was comparable between acetylcholine receptor antibody seropositive and seronegative patients. Two or more CSIS prescriptions significantly increased the frequency of cancer, especially cancers in the digestive organs (p = 0.0026), male genital organs (p = 0.0037) and skin (p < 0.0001).

CONCLUSIONS

Most extrathymic cancer types in MG were observed in TAMG and LOMG patients, and there was a clear correlation between CSIS exposure and cancer risk. This study sheds light on extrathymic cancers also in non-thymoma MG.

Myasthenia Gravis and Large Granular Lymphocytic Leukemia: a rare association

Myasthenia gravis (MG) is an autoimmune neuromuscular junction disorder sometimes observed in hematologic malignancies as a paraneoplastic syndrome. T-cell Large Granular Lymphocytic Leukemia (T-LGLL) is a rare lymphoproliferative clonal frequently associated with autoimmune disorders. Here we report two patients with T-LGLL who developed MG. In both patients the MG was bulbar without generalized weakness and did not involve the thymus. The treatment of T-LGLL led to the resolution of MG symptoms and decrease in acetylcholine receptor antibody titers in both patients suggesting a causative association.

Other Iatrogenic Immunodeficiency-Associated Lymphoproliferative Disorders, Diffuse Large B-Cell Lymphoma Type, in a Patient with Behçet's Disease Treated with Cyclosporine A

A 40-year-old man had been treated for Behçet's disease (BD) with cyclosporine A (CsA) for 14 years. He presented multiple lymphadenopathies with fever. Histological examination of surgical biopsy showed other iatrogenic immunodeficiency-associated lymphoproliferative disorders, diffuse large B-cell lymphoma type with positivity for Epstein-Barr virus encoding RNA-1 (EBER-1). BCL2-IgH, BCL6-IgH, and MYC-IgH translocations were not detected. CsA was stopped, and R-CHOP therapy was initiated. However, his lymphoma was chemotherapy resistant and rapidly progressed. To the best of our knowledge, this is the first case of diffuse large B-cell lymphoma that occurred in a BD patient treated with CsA reported in English. Both BD and CsA are associated with the pathogenesis of lymphoma. We also describe extremely rare cases in the form of a literature review.

Neonatal thymectomy in children-accelerating the immunologic clock?

The thymus is critical for central tolerance and diverse T-lymphocyte repertoire development, to provide lifelong defense against pathogens while maintaining self-tolerance. Peak thymic output occurs in utero, during infancy, and in early childhood, diminishing throughout life. Infants with congenital heart disease requiring sternotomy often undergo thymectomy to clear the surgical field. The long-term effects of early thymectomy are just being appreciated. Many patients remain asymptomatic despite immunologic findings mirroring those of immunosenescence. Few develop increased infection or lymphoreticular malignancy risk. When considering the effects of infant thymectomy, patients with partial DiGeorge syndrome or hypomorphic recombination-activating gene (RAG) mutations may be instructive. These patients are lymphocytopenic, with increased early-onset infection and autoimmunity risk that is not seen in most patients who underwent thymectomy during infancy. The thymic structure of patients with partial DiGeorge syndrome or hypomorphic RAG is abnormal, with disrupted architecture inclining to perturbation of central tolerance. Similar findings may be seen in patients with myasthenia gravis, although disrupted peripheral tolerance may play a greater role in autoimmunity development. In conclusion, thymectomy during infancy may increase future risk of infection or autoimmunity, with premature immunosenescence mediated through disruption of central and peripheral tolerance mechanisms initiated by early cessation or diminution of thymic output. Ideally, some thymic tissue should be preserved at the time of surgery.

Mucosa-associated lymphoid tissue lymphoma of the accessory parotid gland presenting as a simple cheek mass: A case report

RATIONALE

Mucosa-associated lymphoid tissue (MALT) lymphoma, also known as extranodal marginal zone B-cell lymphoma, usually occurs in the gastric mucosa, lung, lacrimal glands, and salivary glands. MALT lymphoma arising from the accessory parotid gland is extremely rare and can therefore be easily confused with other types of soft tissue masses.

PATIENT CONCERNS

A 56-year-old woman presented with a 1-month history of a mass on the left cheek. The mass was hard and nontender. She had a history of thymectomy 26 years ago due to myasthenia gravis.

DIAGNOSIS

A soft tissue tumor measuring 2.5 × 0.8 cm was identified in the left accessory parotid gland on ultrasonography and enhanced computed tomography (CT). Additionally, CT revealed enlargement of both lacrimal glands and an enhancing mass in the right retropharyngeal space. Under suspicion of a malignant soft tissue tumor, ultrasonography-guided fine needle aspiration biopsy was performed, with findings suggestive of marginal zone B-cell lymphoma of the accessory parotid gland.

INTERVENTIONS

The patient was transferred to the department of hematology for immunochemotherapy.

OUTCOMES

The patient has received 6 cycles of rituximab with cyclophosphamide, vincristine, and prednisone chemotherapy. After 6-month follow-up, enhanced CT demonstrated complete remission. Now she is currently under periodic follow-up.

LESSONS

Physicians and surgeons should be aware that MALT lymphoma can occur in the accessory parotid gland. When this is suspected, careful history-taking, imaging workup, and biopsy are essential for accurate diagnosis and treatment.