Atypical Parathyroid Adenoma: A Diagnostic DilemmaT. Seth Tudor PGY3Freeman Health System Joplin, MOOklahoma State University

Learning Objectives: Parathyroid adenoma (PA) vs parathyroid carcinoma (PC) Clinical signs and symptoms Laboratory and radiological studies Intraoperative findings Histopathology Management

Case Presentation 05/23/13 J.C. 66 yo man hoarseness, SOBwE voice for one month Difficulty swallowing pills, and straining, can only whisper PMH- OA, DM2, HTN, CAD PSH- T&A, Coronary stenting 2005, vasectomy FH- OA, CAD, hypothyroidism SH- 20 year smoking history, ETOH once a month PE- No cervical LAD or mass Endoscopy- L paramedian TVC paralysis Plan- CT neck and chest with contrast

CT Results

CT Results

CT Results

Follow Up CT- L posterior inferior thyroid mass 36x20mm Hoarseness stable Upon questioning, had elevated serum Ca (11.5 on 05/01/11) Denied renal, bone, psychiatric symptoms TSH/FT4 WNL No sx of hypo/hyperthyroidism Plan- PTH, serum Ca and albumin, Sestamibi if indicated

Follow Up PTH 117.1, Ca 11 Sestamibi

Intraoperative findings L neck exploration with parathyroidectomy, thyroid lobectomy Pre/post op PTH- 146.1/104.8 (10.4 two hrs post op) 2x3cm fibrous gray capsule RLN encased within (sacrificed) Adherent to trachea, thyroid, esophagus Tissue lateral to trachea/esophagus resected en bloc Frozen section consistent w hypercellular PA

Histopathology Results Nodular growth of parathyroid tissue with hypercellularity Fibrotic bands surrounding capsule, but no parenchymal inv. Abuts but does not invade thyroid gland Fibrosis involving nerve tissue, but no perineural invasion Hemorrhage and necrosis in capsule, but no vascular inv. No cellular atypia or increased mitotic figures Fibrotic changes felt to be degenerative in nature, rather than

evidence of carcinoma Final Dx- Atypical parathyroid adenoma

Histological Findings

Histological Findings

Parathyroid CA

Parathyroid CA vs Adenoma Clinical findings

PC PA

Neck Mass Common (31-70%) Rare (<2%)Hoarseness Uncommon (1-14%) Rare (<<1%)Average Age 45-60 55-70Women : Men 0.58 3.12Renal Involvement* Common (32-80%) Rare (4-18%)Skeletal Involvement* Common (34-91%) Rare (<5%)Psychiatric Involvement Common RareRenal & Skeletal Disease Common RareAsymptomatic Rare (<5%) Common (>80%)

Parathyroid CA vs Adenoma Clinical findings

PC PA

Neck Mass Common (31-70%) Rare (<2%)Hoarseness Uncommon (1-14%) Rare (<<1%)Average Age 45-60 55-70Women : Men 0.58 3.12Renal Involvement* Common (32-80%) Rare (4-18%)Skeletal Involvement* Common (34-91%) Rare (<5%)Psychiatric Involvement Common RareRenal & Skeletal Disease Common RareAsymptomatic Rare (<5%) Common (>80%)

Parathyroid CA vs Adenoma Radiology and Laboratory findings

PC PATumor Size (p<0.01) 30.5±9.4mm 20.6±8.2mmTumor >30mm Frequent Rare (<<1%)Mean Total PTH (p<0.01) 693±1128.1 (97-4700) 125.86±83.5 (66-916)

Median Total PTH 212 95 Mean Total Ca (p<0.01) 14.08±2.86 (9.8-24) 11.19±0.68 (10.6-18.9)

Median Total Ca 14 11

Parathyroid CA vs Adenoma Radiology and Laboratory findings

PC PATumor Size (p<0.01) 30.5±9.4mm 20.6±8.2mmTumor >30mm Frequent Rare (<<1%)Mean Total PTH (p<0.01) 693±1128.1 (97-4700) 125.86±83.5 (66-916)

Median Total PTH 212 95 Mean Total Ca (p<0.01) 14.08±2.86 (9.8-24) 11.19±0.68 (10.6-18.9)

Median Total Ca 14 11

Parathyroid CA vs Adenoma Intraoperative findings

PC PA

Gross Texture Firm SoftGross Color Gray-White Brown-YellowCystic Component 21% Rare (undocumented?)Fibrosis Common RareRLN Involvement Uncommon RareMass (g) 2-10 <3

Parathyroid CA vs Adenoma Intraoperative findings

PC PA

Gross Texture Firm SoftGross Color Gray-White Brown-YellowCystic Component 21% Rare (undocumented?)Fibrosis Common RareRLN Involvement Uncommon RareMass (g) 2-10 <3

Parathyroid CA Histopathology Schantz and Castleman Criteria (1973) Fibrous bands forming trebecular architecture intersecting tumor Capsular invasion Vascular invasion Mitotic activity within tumor cells

Not exclusive to PC, may be found in atypical PA Frozen section is not able to reliably distinguish

Parathyroid CA vs Adenoma Management of PC En bloc resection of tumor Sacrifice of RLN* Central compartment neck dissection Close, frequent PTH and serum Ca follow up

Management of PA Exploration and excision of adenoma Spare surrounding tissue, as it is a benign process

Comprehensive Treatment Preop suspicion & intraoperative findings En bloc resection of tumor Initial resection is best chance of cure for PC If RLN involved in suspicious tumor, resection is appropriate Iacobone (2004) demonstrated RLN in 11/14 reoperations Lee (2009) spontaneous hemorrhage, abscess, cysts in PA may cause

neuropraxia/axonotmesis with good chance of recovery postop

Central neck dissection Ipsilateral thyroid lobectomy

Pitfalls Must recognize high risk clinical/laboratory scenarios Must recognize high risk intraoperative findings Incomplete resection on primary surgery Insufficient follow up

Questions/Discussion

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