Fortbildungen / Formations continues 2012 - IUMSP

DER SELTENE FALL
CASTLE «Carcinoma
showing thymus-like
differentiation of the
thyroid»: a rare cause
of neck mass
M. Zare, S. Cochet, M. Pusztaszeri, P. -Y. Dietrich
Keywords: CASTLE, solid cell nests, CD5
Introduction
The presence of a mass in the neck gives rise to a wide
differential diagnosis, ranging from benign to serious aetiologies.
Congenital neck masses are usually present at
birth and are often cysts originating from branchial clefts
or the thyroglossal duct. In�ammatory neck masses are
generally related to enlarged lymph nodes and have various
infectious origins. Malignant diseases have always to
be considered in case of neck masses. The most common
cancers are metastatic lymph nodes from head and neck
squamous cell carcinomas, thyroid tumours or lymphomas.
Rare (e.g., paraganglioma or schwannoma) or even
exceptional tumours should also be included in the differential
diagnosis, such as CASTLE tumour.
Case report
A 58–year-old Caucasian man developed hoarseness and occasional
dysphagia to liquids and solids in 2010. Clinical
examination revealed a palsy of the left vocal cord and a
slightly painful left neck mass. The total body scan showed
a 4 cm sized left neck mass attached to the inferior part of
the thyroid (Figure 1). A �ne needle aspiration biopsy was
not conclusive. Panendoscopy was normal. Neck MRI con-
�rmed the presence of a mass with apparent involvement of
both the thyroid and the trachea, and suspicious left para-
and pre-tracheal nodes. A surgical biopsy was performed
and the diagnosis of moderately to poorly differentiated
squamous cell carcinoma was established. The patient underwent
total removal of the mass with tumorectomy, dissection
of group IV lymph nodes, left hemi-thyroidectomy
and resection of the third to the �fth tracheal rings.
The resection specimen showed a whitish and �brotic mass
partly invading the thyroid, and extending to the tracheal
rings and the skeletal muscles with macroscopically positive
surgical margins. Microscopically, �brous septa surrounded
large irregular nests of poorly differentiated ovoid
cells with an amphophilic cytoplasm, round nucleus,
�ne granular chromatin and central nucleoli (Figure 2).
There were a few number of mitosis and rare images of pe-
Figure 1: Contrast-enhanced CT (coronal view) shows a 4 cm
sized cervical mass (black arrow) shifting the trachea to the
right, with a possible invasion of the tracheal cartilage (small
white arrow).
A B
Figure 2: H&E staining shows (A) a close contact between the normal thyroid (left part, arrow) and a tumour composed of neoplastic
cells separated by large �brous septa. (Magni�cation x 20) and, (B) at higher magni�cation (x 200) large nests of ovoid tumour cells
(white triangle) surrounded by lymphocytes (white arrow).
170 Schweizer Krebsbulletin � Nr. 2/2012