Cytological Diagnostic Approach in 3 Cases of Langerhans Cell Histiocytosis Presenting Primarily as a Thyroid Mass

Langerhans cell histiocytosis of thyroid and bilateral parotid diagnosed on fine needle aspiration cytology

LCH has a distinct site predilection and cytological feature. However, it can cause diagnostic difficulties at unusual sites or deviated cytomorphology. FNAC is a minimally invasive procedure that can be performed in any organ (parotid and thyroid where biopsy is not commonly indicated) and multiple sites/organs simultaneously for diagnosis. FNA sampling can also help with cell block preparation for performing immunohistochemistry and molecular studies if necessary.

Analysis of thyroid involvement in children and adult Langerhans cell histiocytosis: An underestimated endocrine manifestation

BACKGROUND

Langerhans cell histiocytosis (LCH) is a rare disease caused by the clonal expansion of CD1a+/CD207+ LCH cells. The thyroid involvement in LCH has mostly been described in case reports.

METHODS

We retrospectively evaluated the clinical characteristics, diagnosis, and treatment of 27 children and adult patients with thyroid LCH in our center between 2010 and 2021.

RESULTS

The incidence of thyroid LCH was 14.00% (7/50) in children and 10.10% (20/198) in adults, respectively. Among patients with thyroid involvement, 81.5% presented with diabetes insipidus (DI) as the first symptom, and 51.9% complained of neck swelling or mass. Children and adults with thyroid LCH had higher frequencies of the hypothalamic-pituitary axis (HPA) (children: 100% vs. 62.8%, P=0.05; adult: 95% vs. 42.1%, P<0.001), the lung (children: 85.7% vs. 25.6%, P=0.004; adult: 70% vs. 50.6%, P=0.099), and a lower frequency of bone (children: 14.3% vs. 55.8%, P=0.049; adult: 45% vs. 73.6%, P=0.008) involvement than patients without thyroid involvement. Patients with thyroid LCH had a higher frequency of primary hypothyroidism and a lower frequency of euthyroidism than patients without it. The two major types of ultrasound imaging were diffuse (55%) and nodular type (45%). The standardized uptake value of thyroid on 18-F-fluorodeoxyglucose positron emission tomography/computed tomography was 5.3-12.8. The diagnoses were confirmed using thyroid aspiration (54.5%) or surgery (45.5%). In addition, thyroid LCH combined with papillary thyroid carcinoma was not rare (2/27).

CONCLUSION

Thyroid involvement in LCH is not rare. Furthermore, identifying thyroid involvement can facilitate the pathological diagnosis of LCH. Therefore, the possibility of thyroid LCH should be fully investigated in patients with DI, primary hypothyroidism, abnormal thyroid ultrasound results, and multi-system disease. In addition, thyroid aspiration can confirm suspected thyroid LCH. Finally, special attention should be paid to evaluating HPA and pulmonary involvement in thyroid LCH.

Primary Langerhans Cell Histiocytosis in Thyroid

Background

Langerhans cell histiocytosis (LCH) is a rare group of neoplastic diseases resulting from Langerhans dendritic cells. The most common site (80%) is bones. Thyroid gland involvement is exceedingly rare and usually expected to be seen as a part of multisystemic disease.

Case Report

We present a 45 year old male patient operated due to multinodular goiter and neck pain, and diagnosed with LCH in his postoperative pathologic examination. As a result of the systemic screening performed after the pathological diagnosis, the disease was interestingly localized to the thyroid gland. Systemic involvement did not develop in the two-year follow-up of the patient who did not receive additional chemotherapy treatment.

Conclusion

It is difficult to diagnose LCH in the thyroid gland before surgery. Although surgical treatment with or without chemotherapy is recommended, surgery is not recommended alone since it is generally systemic involvement. However, in primary thyroid LCH cases limited to the thyroid gland, we recommend that only total thyroidectomy treatment should be kept in mind.

Langerhans cell histiocytosis of the thyroid complicated by papillary thyroid carcinoma: A case report and brief literature review

RATIONALE

Langerhans cell histiocytosis (LCH) involves mainly the skin and bone and rarely the thyroid. Meanwhile, papillary thyroid carcinoma (PTC) is the most common subtype of thyroid cancer. Both LCH and PTC could make the thyroid enlarged and hypermetabolic. The coincidence of these 2 events in a patient is rare, and this paper aimed to report such case.

PATIENT CONCERNS

A 40-year-old man presented with polyuria and polydipsia for 5 years. The symptoms had been relieved well by drug therapy for >4 years, until the drugs could not control the symptoms anymore and an extensively enlarged thyroid gland was noticed.

DIAGNOSES

Thyroid ultrasound showed a nodule with microcalcification in the upper right lobe, positron emission tomography/computer tomography scan demonstrated thyroid hypermetabolism, and fine needle aspiration (FNA) revealed PTC. Right lobectomy of the thyroid and cervical lymph node biopsy verified the diagnosis "LCH of the thyroid complicated by PTC."

INTERVENTIONS

The ultrasound-guided FNA biopsy was performed prior to right lobectomy of the thyroid and cervical lymph node biopsy. Postoperative histopathological examination confirmed the diagnosis, after which the patient received adjuvant chemotherapy.

OUTCOMES

After 5 cycles of adjuvant chemotherapy, the patient had been followed up for 2 years. LCH was controlled satisfactorily and there was no significant sign of recurrence or metastasis of PTC.

LESSONS

LCH of the thyroid complicated by PTC is rare. Thyroid involvement should always be considered in the differential diagnosis of LCH patients. Surgery for PTC followed by chemotherapy for LCH may be the suitable treatment.