Patient description: A 16-year-old girl came to the clinic complaining of weight gain and abnormal menstrual cycles. Her BMI was 24, but she has gained 5 kg in the past few weeks. She gets tired more frequently and does not have energy to go dancing with her friends. Her lab results were remarkable for high TSH levels (15 mU/L) and low free T4 levels (0.18 ng/dl). Her anti-TPO levels were extremely high (136 IU/ml). She was diagnosed with Hashimoto disease. She does not smoke and she is not sexually active.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Metastatic Thyroid Gland Carcinoma Poorly Differentiated Thyroid Gland Carcinoma Stage IVA Thyroid Gland Anaplastic Carcinoma AJCC v8 Stage IVB Thyroid Gland Anaplastic Carcinoma AJCC v8 Stage IVC Thyroid Gland Anaplastic Carcinoma AJCC v8 Thyroid Gland Anaplastic Carcinoma Unresectable Thyroid Gland Carcinoma Histologically confirmed anaplastic thyroid or poorly differentiated thyroid carcinomas Patients deemed to have unresectable locoregional disease or metastatic disease. Patients who are unwilling to undergo surgery or external beam radiation are also eligible Patients with poorly differentiated thyroid cancer must have at least one target lesion by version 1.1. This is not a requirement for ATC patients Total bilirubin =< 1.5 x upper limit of normal (ULN). Total bilirubin: 3 x ULN for patients with Gilbert's syndrome Aspartate aminotransferase (AST) serum glutamic-oxaloacetic transaminase (SGOT) / alanine aminotransferase (ALT) serum glutamate pyruvate transaminase (SGPT) =< 2.5 x ULN, (5 x ULN for patients with concurrent liver metastases) Serum creatinine =< within 1.5 x ULN Absolute neutrophil count (ANC) >= 1.0 x 10^9 /L Platelets (PLT) >= 100 x 10^9 /L For patients receiving therapeutic anticoagulation: stable anticoagulant regimen and stable international normalized ratio (INR) during the 28 days immediately preceding initiation of study treatment Subjects must be willing to undergo tumor biopsy prior to and after treatment with atezolizumab, unless in the opinion of the treating physician, a biopsy is not feasible or safe  Subjects with an active, known or suspected autoimmune disease. Subjects with type I diabetes mellitus on stable insulin regimen, hypothyroidism only requiring hormone replacement, skin disorders (such as vitiligo, psoriasis, or alopecia) not requiring systemic treatment, or conditions not expected to recur in the absence of an external trigger are permitted to enroll For patients not receiving therapeutic anticoagulation: INR or partial thromboplastin time (aPTT) > 1.5 x ULN within 28 days prior to initiation of study treatment Prior treatment with anti-PD-1, or anti-PD-L1 therapeutic antibody or pathway targeting agents. Patients who have received prior treatment with anti-CTLA-4 may be enrolled, provided the following requirements are met: Minimum of 12 weeks from the first dose of anti-CTLA-4 and > 6 weeks from the last dose, and no history of severe immune-related adverse effects from anti-CTLA 4 (National Cancer Institute [NCI] Common Terminology for Adverse Events [CTCAE] grade 3 and 4) Known clinically significant liver disease, including active viral, alcoholic, or other hepatitis; cirrhosis; fatty liver; and inherited liver disease History of human immunodeficiency virus (HIV) infection or active hepatitis B (chronic or acute) or hepatitis C infection Patients with past or resolved hepatitis B infection (defined as having a negative hepatitis B surface antigen [HBsAg] test and a positive anti-HBc [antibody to hepatitis B core antigen] antibody test) are eligible. However, patients with past or resolved hepatitis B virus (HBV) should be monitored for reactivation by a specialist. Patients positive for hepatitis C virus (HCV) antibody are eligible only if polymerase chain reaction (PCR) is negative for HCV ribonucleic acid (RNA) Pregnant or lactating women. All pre-menopausal women being screened must have a negative serum pregnancy test within 14 days prior to commencement of dosing. Women of non-childbearing potential may be included if they are either surgically sterile or have been postmenopausal for >= 1 year. Fertile men and women must use an effective method of contraception during treatment and for at least 6 months after completion of treatment as directed by their physician Untreated brain metastases Chemotherapy within 21 days of enrollment with the exception of paclitaxel or nab-paclitaxel (Abraxane). Patients who have received one course of these agents prior to study entry are eligible. (One course of weekly paclitaxel or nab-paclitaxel is 3 doses. One course of every 3 week dosing of paclitaxel or nab-paclitaxel is 1 dose). Patients who have received prior radiosensitizing chemotherapy are eligible The use of corticosteroids is not allowed for 10 days prior to initiation of atezolizumab except patients who are taking steroids for physiological replacement. Inhaled or topical steroids, and adrenal replacement steroid doses are permitted in the absence of active autoimmune disease. This does not apply to patients receiving steroids as pre-medications for paclitaxel administration Grade >= 2 uncontrolled hypertension (patients with a history of hypertension controlled with anti-hypertensive medication to Grade =< 1 are eligible)