DISCUSSION
Thymoma, a rare malignancy, accounts for 20%-25% of mediastinal tumors
and exhibits a diverse range of clinical manifestations and an elusive
etiology.4,5 The initial presentation of our patient
was characterized by recurrent chest pain over five months, followed by
a more subacute presentation with exertional dyspnea and decline in
functional status. Although many cases of thymoma are asymptomatic, the
indolent course, and pericardial involvement observed in this case is
atypical and highlights the need for a high index of suspicion in
patients presenting with persistent or recurrent
symptoms.1 Riedel et al. previously reported several
cases of indolent thymoma, corroborating our observation that thymoma
can exhibit a largely indolent growth pattern.6
In this case, the decision to opt for a high-complexity
fluoroscopy-guided pericardiocentesis was influenced by several key
factors, each carrying significant implications for clinical practice.
The patient’s initial presentation included a series of concerning
symptoms, most notably exertional dyspnea and a significant decline in
functional status, necessitating immediate symptomatic relief. In
addition, the CT scan revealed an anterior mediastinal mass accompanied
by a moderate to large pericardial effusion, yet without any indicators
of significant obstruction or tamponade physiology, thereby allowing for
a planned, rather than urgent, approach. Thus, fluoroscopy-guided
pericardiocentesis, being a minimally invasive procedure, was the
modality of choice serving a dual purpose: it facilitated symptom relief
by enabling the removal of pericardial effusion and concurrently allowed
for the examination of the fluid for malignant
cells.7,8 However, prior studies have showed that
cancer cells can migrate to the pericardial fluid and performing
pericardiocentesis might pose risk for
dissemination.9,10 Therefore, there existed
substantial concerns regarding malignancy and the potential risk of
tumor dissemination. In fluoroscopy-guided pericardiocentesis, the
utilization of fluoroscopy ensured precision in needle placement,
minimizing the risk of complications such as cardiac tamponade or
puncture of surrounding structure, in addition to reducing the risk of
malignant cells migration.
The histological classification of thymomas predominantly relies on
tumor cytomorphology. However, the World Health Organization (WHO)
classification has undergone several modifications over time, leading to
a more nuanced understanding of specific tumor
types.11 In this patient, the core biopsy tissue
analysis confirmed a thymoma, subtype WHO B2, characterized by a mixture
of small round lymphocytes and epithelial cells with ill-defined cell
borders, separated by broad fibrous bands and highlighted by
immunohistochemical staining for CK5 and p40. The absence of necrosis or
cytologic features of carcinoma suggested a lower risk of aggressive
behavior. The chosen subtype (WHO B2), while being more aggressive than
B1 subtype, is not linked with high invasiveness or aggressive
migration, reaffirming the suitability of the chosen
approach.11 However, the literature scarcely addresses
the indolent course of the B2 subtype, making this case potentially
indicative of broader implications that warrant further exploration and
research.12
Within the expansive arsenal for managing thymoma, surgical resection is
a cornerstone, especially for localized entities. The indolent nature
and subacute presentation of our case allowed for a non-urgent,
thoughtful approach to intervention. This aligns with the case reported
by Azuma et al., where a giant tumor necessitated immediate surgical
intervention.13 In Azuma’s case, the patient showed
various clinical symptoms and was also diagnosed with WHO B2 thymoma.
Despite being the same subtype, our patient’s gross pathology of the
tumor showed a more aggressive and expansive pattern, which further
testified to the surgical approach. In addition, our patient showed a
concurrent pericardial effusion, which necessitated an in-depth
exploration. However, it’s worth noting that B2 subtype thymoma has a
high recurrence rate at 18.6% for the particular subtype and up to 50%
for Masaoka stage.14 This implies necessity for
vigilant postoperative surveillance and comprehensive long-term
management plan.
Comparing this case with similar instances documented in the literature
highlights some distinct characteristics. For example, Bakhriansyah J.
et al. detailed a case of a patient with advanced thymoma complicated by
purulent pericarditis.15 Similar to our approach,
Bakhriansyah J. et al. also chose fluoroscopy-guided pericardiocentesis,
reinforcing the safety and effectiveness of this method. However, our
case manifested a more indolent course and a semi-emergent situation,
contrasting with the more acute presentation in the case reported by
Bakhriansyah J. et al. This difference underscores the variability in
the clinical presentation of thymomas and highlights the necessity for
individualized, case-by-case decision-making in managing these patients.
Khan et al. reported a case with cardiac tamponade, which they chose to
open an emergent pericardial window for pericardial
drainage.16 This difference in approach between the
case reported by Khan et al. and our own highlights the importance of
considering the overall health status of the patient and the specific
characteristics of the tumor when selecting an appropriate treatment
strategy. In the case reported by Khan et al., the presence of cardiac
tamponade, a life-threatening emergency, necessitated immediate
intervention to drain the pericardial effusion, thereby justifying the
choice for an emergent pericardial window. In contrast, our patient
presented with a more subacute course, without signs of significant
obstruction or tamponade physiology, allowing us to opt for a less
invasive, yet equally effective, fluoroscopy-guided pericardiocentesis.
This not only provided immediate symptomatic relief but also enabled us
to obtain a sample for cytological examination, thereby aiding in the
diagnosis and subsequent treatment planning.