Micropapillary thyroid cancer (microPTC, < 10 mm, devoid of nodal metastases) is traditionally treated with surgery. Total thyroidectomy is the most extensive demolitive surgery, thyroid lobectomy has entered the guidelines in recent years. Very recent international guidelines  recognize minimally invasive ultrasound-guided thermoablation (TA) with laser, radio frequency (RFA) or microwave (MWA) intervention as a possible alternative to open surgery in patients with contraindications to surgery or in patients who refuse it.
74-year-old woman in good health.
In 2018 left mastectomy surgery for multiple foci of ductal adenocarcinoma.
During the follow-up for breast cancer she had a thyroid ultrasound in January 2022 with a suspected 7 mm microPTC (TIRADS 6); no lymphadenopathies were found.
In another Clinic she had thyroid fine needle aspirate with cytological finding of blood material, scarce follicular cells with oxyphilic cells, macrophages. Cytological classification Thy 3° = Betesda III). Low risk indeterminate.
The local endocrinologist saw the suspicion ultrasound and cytology He sent the patient to surgery with indication to total thyroidectomy, which the patient refused.
February 2022 the patient turned to E.T.C. The ultrasound was repeated and the ultrasound suspicion of microtumor, free of lymphadenopathies was confirmed (Figs. 1 – 3). With a Chiba 5 cm long G 27 needle plugged with a Terumo 20 ml syringe connected with a Cytofast aspiration pump, fine needle aspirate was repeated. A total of 8 slides were set up, 4 fixed in alcohol for the Papanicolaou staining, 4 fixed dry for the May Grünwald Giemsa staining. The finding was: abundant material, numerous follicular cells with clear and irregular nuclei, grooves and nuclear inclusions, poor colloid, macrophage cells. Classification Thy 5 (Bethesda VI). Papillary tumor.
At E.T.C., considering the patient’s refusal of surgery, according to recent international guidelines , RFA minimally invasive ultrasound-guided intervention was proposed.
RFA surgery was performed using Starfix electrode needle of 7 cm in length, 5 mm exposed tip cooled internally with saline sterile solution at -5 °C, Starmed RF generator. After sterile field set up, general sedation with Fentanyl, Midazolam and Propofol was performed by the anesthesiologist. The operato under ultrasound assistance injected lidocaine 2% pericapsular for local anaesthesia. Then followed ultrasound-guided hydrodissection with 21 G needle, infusion of glucose at a temperature of +5 °C obtaining cleavage of the thyroid gland from the tracheoesophageal groove where recurrent laryngeal nerve decurs. The electrode needle was positioned both transistmically and longitudinally for complete and definitive ablation of the tumor with a security ring of surrounding healthy tissue (Fig. 4). Administration of 0.40 Kcal, equal to 1680 Kjoules, in an effective time of 2’15”, power 30 Watts. Technique “moving shot”. Electrode needle extraction and compression for 5′ of the puncture site. Sterile patch and ice pack. The intervention, including all preliminary maneuvers is completed in 15 minutes with total ablation of the microPTC and a surrounding safety ring of 2 mm. Ablation is demonstrated by the complete absence of vascularization verified with the microV function of the ultrasound (Figs. 5 – 6). No side effects at all.
The patient wakes up promptly, has no memory of the ablation and thanks the team of E.T.C.
The case presented demonstrates how important it is that a microPTC diagnostic fine needle aspiration is performed. Fine needle aspirations conducted with inappropriate techniques often lead to indeterminate cytology, as has happened in the case presented. At E. T. C. the fine needle aspiration cytology is always repeated in indeterminate lesions because the result of indeterminate, rather than from real indeterminacy of the lesion, often depends on improper techniques of execution of fine needle aspiration cytology (use of needle of unsuitable gauge, use of open needle rather than Chiba needle with stylet, failure or partial targeting of the lesion, excessive or insufficient aspiration -the pump Cytofast allows to quantitatively dose the negative suction pressure-, slides smears not applied artfully) and/or insufficient material extracted.
This clinical case shows that microPTC can be treated with RFA, solving the problem in minutes with minimal inconvenience to the patient. The side effects, taken the necessary precautions, in particular the hydrodissection for the protection of the recurrent laryngeal nerve, and the compression exerted on the puncture site after the extraction of the needle to avoid bruises and bleeding, are minimal.
Thermoablation of microPTC was proposed in 2013 with lasers by Valcavi et al . Subsequent literature has shown that treatment with microPTC CT yields the same results as surgery, sparing the gland or part of it and the discomfort associated with open surgery. Various methods of TA have been proposed: laser ablation (LA) , microwave (MWA)  and RFA . Compared to Laser and MWA, the RFA has the advantage of being better controllable and not producing carbonization. Specially designed electrodes are available, such as the one used in the present case, with an exposed tip of 5 mm, particularly suitable for the treatment of microPTC.
It is likely and desirable that in the near future microPTC will be treated with TA, RFA in particular, rather than traditional surgery.
LEGEND TO THE FIGURES
Fig. 1. – B mode, transverse scan. MicroPTC < 1 cm (dimensions shown on figure) left lobe that does not break the capsule, intrathyroid.
Fig. 2 – B mode, sagittal scan. Micro PTC. No pathological lymph nodes are seen in either the central or lateral compartments of the neck.
Fig. 3 – microv, transverse (syn panel) and sagittal (right panel) scans. It proves a vascularization predominantly perinodular, but also intranodular, chaotic.
Fig. 4 – RFA. Longitudinal insertion of the electrode.
Fig. 5 – B Mode, MicroPTC ablated. The diameters of the ablation, represented by the hypoechoic tissue, are 4-6 mm higher than the pre-blazon ones, demonstrating the destruction of a safety ring all around the microPTC
Fig. 6 – microv of the ablated MicroPTC. It is shown disappearance of vascularization at the ablated tissue.
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