Clinical-cytohistological correlation of cervicofacial congenital cysts
Correlación clínico-citohistológica de los quistes congénitos cervicales

The authors establish a correlation study between the clinical and cytological diagnoses of cervicofacial congenital cystic masses. They repeatedly use the abbreviation FNAB for Fine Needle Aspiration Biopsy. This is confusing since the test subjected to analysis in the article obtains cytological and not histopathological material. The term FNAP (PAAF in Spanish) as abbreviation of Fine Needle Aspiration Puncture is widely accepted and published in the Spanish language literature. Surgical biopsy with its histopathological study is the gold standard. A very short description is made of the cervical cysts in the introduction. The authors restrict their study to three types of congenital cervical cysts, these being thyroglossal duct, branchial and dermoid cysts, even though there are others that they mentioned such as cavernous lymphangiomas (cystic hygromas), parathyroid, bronchogenic, thymic, laryngocele, teratoma cysts, etc. and some more that deserve clinical attention.^(1-3)

In the description of the cysts that they deal with later on, the gross aspect of the content of one of them, the dermoid cyst, is commented on. They state that the cavity is full «of serous material». The serous material (similar to serum) is not characteristic of this type of cyst. In the dermoid cyst, a pasty material made up of keratin and fat from the secretion of the dermal appendages found in its wall is obtained.

In the mentioned description, no reference is made to the histopathological structure of the lesions. It is information that not only has academic but also practical interest and helps to explain the cytology results. The thyroglossal cysts in the upper neck have a squamous lining, while in the lower neck, they have a cubic epithelial lining. There may be thyroid folicules in the wall so that colloid material and folicular cells may be recognized in the aspiration. The certainty cytological diagnosis can only be made in the latter case.

The branchial cyst whose content generally has a gross mucoid appearance may also be lined by cubic, ciliated cylindrical or squamous epithelium so that its differential diagnosis with the thyroglossal cyst may be very difficult from the strictly cytological point of view. It is well known that the branchial cyst has a well organized lymphoid component in its wall. In the puncture, the presence of this component, together with benign epithelial elements, lead us to a branchial cyst diagnosis, but always taking its location into account since some lymphoepithelial cysts of the salivary gland show a very similar appearance.

The dermoid cyst cytology is impossible to differentiate from that of the infundibular cyst since both show a large amount of intermediate and superficial squamous cells with keratin remains.

Other cysts such as the parathyroid one need other techniques like the demonstration of parathyroid hormone in the liquid (PTH) for its confirmation.^{(2, 4)}

The possibilities when faced with a cervical tumor are very logically established in the discussion and in addition to the congenital nature, the infectious (inflammatory in general) and neoplastic nature are also included. Clinical data of age, location, evolution time, background, etc provide a very important approximation to the diagnosis which, as the authors state, is reinforced through FNAP verification.

In their casuistry, the differential clinical diagnosis is frequently suggested with reactive lymphadenopathy. However, in our experience, these patients arrive with the clinical suspicion of malignancy: metastasis or lymphoma since the cystic lesions generally acquire a size that leads to the suspicion of malignancy. The profitability of the FNAP in this type of differential diagnosis is obviously much greater than that of the clinical diagnosis and its main objective.^(5,6)

From the discussion of the authors, the following question can be deduced: From the point of view of efficacy, economy, fastness, etc, can the FNAP avoid imaging techniques?

The result is not clarified and probably adjusts to the needs of each center. When the delay in the imaging tests is very high, it is evident that the clinicians will use the FNAP as confirmation method of their diagnostic impression. However, the ideal situation would be to perform the imaging techniques before the FNAP so that the diagnostic certainty would be close to 100%. The FNAP, however harmless it is, alters the radiological or ultrasonographic image of the lesion. Knowing the exact site of the lesion and of the structure it depends on enormously helps its correct diagnosis, especially in the least frequent lesions such as thymic cysts, lymphangiomas or parathyroid cysts in which, due to suspicion, detection of PTH in liquid may be requested, which would provide the key to the diagnosis. On the other hand, situations that may be dangerous, such as paraganglioma puncture, are avoided.

J.A. López García-Asenjo
Servicio de Anatomía Patológica
Hospital Clínico San Carlos.
Madrid, España

References

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2. Armstrong J, Leteurtre E, Proye C. Intraparathyroid cyst: a tumour of branchial origin and a possible pitfall for targeted parathyroid surgery. ANZ J Surg 2003;73:1048-51.

3. el Hag IA, Chiedozi lC, al Reyees FA, Kollur SM. Fine needle aspiration cytology of head and neck masses. Seven years´experience in a secondary care hospital. Acta Cytol 2003;47:387-92.

4. Espinoza L, Molina MA, Gonzalez I, Gracia R. Parathyroid cyst in the differential diagnosis of neck masses. A Case Report. An Pediatr (Barc) 2003;58:188-90.

5. Ustun M, Risberg B, Davidson B, Berner A. Cystic change in metastatic lymph nodes: a common diagnostic pitfall in fine-needle cytology. Diagn Cytoptahol 2002;27:387-92.

6. Costas A, Castro P, Martín-Granizo R, Monje F, Marrón C, Amigo A. Fine needle aspiration biopsy (FNAB) for lesions of the salivary glands. Br J Oral Maxillofac Surg 2000;38:539-42.