Case | Features | Histopathological findings | s-IgG4 (g/L) (ref > 1.35 for RCD, > 2.01 for 2019 ACR/EULAR classification criteria) | RCD | 2019 ACR/EULAR classification criteria |
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1 | Two years prior to IgG4-RD diagnosis: diagnosis of MPA based on petechiae, glomerulonephritis (biopsy proven) and positive MPO-ANCA. Treated with RTX (1A and 1B), followed by AZA maintenance. At time of IgG4-RD diagnosis (under maintenance therapy with AZA monotherapy): left lacrimal gland enlargement. No other manifestations. Deemed to be coexisting MPA and IgG4-RD, with the latter accounting for the dacryoadenitis. The rational was (i) the other vasculitic manifestations were well controlled; and (ii) the previous reports of coexistence of AAV and IgG4-RD. However, we acknowledge the diagnostic uncertainty | Lacrimal gland: LPC infiltrate and storiform fibrosis. > 50 IgG4 + PC/hpf with IgG4/IgG ratio > 0.40 | 0.81 | Probable IgG4-RD | Fulfils entry criterion. Fulfils exclusion criterion (MPO-ANCA) Weighted score = 27 • Histology = 13 • IHC = 14 |
2 | Sinusitis, cough and low-grade fever. Destructive process in sphenoid sinus, lymphadenopathy and lung changes (ground glass opacities and small nodules). ANCA negative. Biopsy without evidence of AAV or malignancy | Sphenoid sinus: LPC infiltrate and fibrosis (without storiform appearance). Abundant IgG4 + PC/hpf (unable to quantitate), with IgG4/IgG ratio > 0.40 | 3.43 | Definite IgG4-RD | Fulfils entry criterion. Fulfils exclusion criterion (fever) Weighted score = 22 • Histology = 4 • IHC = 14 • s-IgG4 = 4 |
3 | Inflammatory mass in nasal septum. No other definite manifestations (albeit possible idiopathic pancreatitis 10 years prior). ANCA negative. Biopsy without evidence of AAV or malignancy | Nasal septum: LPC infiltrate and fibrosis (without storiform appearance). Abundant IgG4 + PC/hpf (unable to quantitate), with IgG4/IgG ratio > 0,3 | 2.08 | Definite IgG4-RD | Does not fulfil entry criterion (nasal septum not a typical organ). No exclusion criteria Weighted score = 15 • Histology = 4 • IHC = 7 • s-IgG4 = 4 |
4 | Chronic rhinosinusitis and arthralgia. Negative ANCA. FDG-uptake in tonsils, oropharynx, and bilateral parotid and submandibular glands. No other manifestations. Positive anti-RNP, but no arthritis or other manifestations suggestive of MCTD or other connective tissue disease | Waldeyers ring: LPC infiltrate. 88 IgG4 + PC/hpf, with IgG4/IgG ratio > 0.4 | 4.30 | Definite IgG4-RD | Fulfils entry criterion. Fulfils exclusion criterion (anti-RNP) Weighted score = 38 • Histology = 4 • IHC = 14 • s-IgG4 = 6 • Two sets of glands = 14 |
5 | Right lacrimal gland enlargement. FDG-uptake in bilateral parotid and submandibular glands. No other manifestations. Positive MPO-ANCA, but no other manifestations consistent with AAV. As there was no evidence of vasculitis or extraglandular vasculitic manifestations, we believe that the presentation was more consistent with IgG4-RD than AAV | Lacrimal gland: LPC infiltrate. > 100 IgG4 + PC/hpf, with IgG4/IgG ratio > 0.4 | 2.30 | Definite IgG4-RD | Fulfils entry criterion. Fulfils exclusion criterion (MPO-ANCA) Weighted score = 36 • Histology = 4 • IHC = 14 • s-IgG4 = 4 • Two sets of glands = 14 |
6 | Lacrimal gland enlargement. FDG-uptake in bilateral parotid glands. No other manifestations | Lacrimal glands: inconclusive | 3.17 | Possible IgG4-RD | Fulfils entry criterion. No exclusion criteria Weighted score = 18 • s-IgG4 = 4 • Two sets of glands = 14 |
7 | Orbital pseudotumor and ipsilateral lacrimal gland enlargement. FDG uptake in bilateral lacrimal and submandibular glands. No other manifestations. Positive MPO-ANCA and microscopic hematuria, with renal biopsy consistent with low-grade AAV (without evidence of IgG4-related kidney disease). Considered to be coexisting MPA and IgG4-RD, with the latter accounting for the head and neck manifestations. However, we acknowledge the diagnostic uncertainty | Lacrimal glands: LPC infiltrate and fibrosis (without storiform appearance). > 90 IgG4 + PC/hpf, unable to estimate ratio | 1.30 | Probable IgG4-RD | Fulfils entry criterion. Fulfils exclusion criterion (MPO-ANCA) Weighted score = 25 • Infiltrate = 4 • IHC = 7 • Two sets of glands = 14 |
8 | Right submandibular gland enlargement and lymphadenopathy. FDG-uptake in right parotid and submandibular glands. No other manifestations | Lymph node: LPC infiltrate. > 100 IgG4 + PC/hpf and IgG4/IgG ratio 0.80 | 6.70 | Possible IgG4-RD (lymph node biopsy not considered) | Fulfils entry criterion. No exclusion criteria Weighted score = 10 • Histology = 4 • s-IgG4 = 6 (lymph node biopsy not used for IHC scoring) |
9 | Pharyngeal fullness and low-grade fever. FDG uptake in oropharynx and lymph nodes. No other manifestations | Waldeyers ring: LPC infiltrate and fibrosis (without storiform appearance). Abundant IgG4 + PC/hpf (uanable to quantify), with IgG4/IgG ratio > 0.50 | 3.40 | Definite IgG4-RD | Does not fulfil entry criterion (oropharynx not a typical organ). Fulfils exclusion criterion (fever) Weighed score = 22 • Histology = 4 • IHC = 14 • s-IgG4 = 4 |