An Uncommon Lung Neoplasm in a Young Patient: Diagnostic Challenges

Abstract

BACKGROUND Adenosquamous carcinoma of the lung (ASC) is a rare subtype of non-small-cell lung carcinoma (NSCLC), histologically defined by the presence of both squamous cell carcinoma and adenocarcinoma components. This aggressive malignancy has been rarely described in young female patients. Due to its low incidence and difficult-to-establish preoperative diagnosis, little is known about the complete clinical course for young patients with this specific NSCLC subtype. Moreover, a history of smoking is positively associated with ASC, but evidence for an association with exposure to secondhand smoke is sparse. CASE REPORT We present the case of a previously healthy 29-year-old woman with a long-standing history of secondhand smoke exposure, who was ultimately diagnosed with advanced ASC via fiberoptic bronchoscopy with transbronchial biopsy after a number of different investigations and treatments performed outside our service. She had visited many clinicians in 4 months of symptoms, initially presented as thoracic pain and cough thought to be due to a complicated pneumonia. Symptoms progressed despite empiric treatment and eventually included low back pain, weight loss, and night sweats. The hypothesis of tuberculosis was then investigated and discarded, at which point, 3 months after the onset of symptoms, she had a CT scan of the chest, revealing a pulmonary mass. She was referred to our hospital to further investigate this finding via fiberoptic bronchoscopy with transbronchial biopsy. During the procedure, she experienced an acute exacerbation of the low back pain, which prompted her admission in the Emergency Department, and she was later admitted to our pneumology ward. An extensive treatment plan including chemotherapy and radiotherapy was initially started, but could not be completed due to rapid disease progression, defined by pulmonary and spine metastatic implants, which limited treatment to palliative care. The patient died 6 months after the initial onset of symptoms. CONCLUSIONS This case report shows the clinical course of a difficult and rare diagnosis, and demonstrates the high level of suspicion required for the early diagnosis of lung neoplasms in young patients.

Figure 1.

CT scan of the chest with a lung window showing a spiculated 15×11 mm nodule in the lower lobe of the right lung (A), pleural thickening in the region of the interlobar fissure (B). Two soft-tissue density nodules in the right upper lobe (C) and in the right lower lobes (D), in addition to a lobed contour mass involving bronchovascular structures of the right pulmonary hilum and causing partial obstruction of the right middle bronchus and ground-glass infiltration in the middle lobe (D).

Figure 2.

Magnetic resonance imaging of the lumbar spine showing reduced height of the L4 vertebral body with hyposignal area in T1 (A) and with heterogeneous contrast enhancement (B) in the upper plateau of L4 with an associated Schmörl node, suggesting a metastatic implant, probably responsible for the patient’s lumbar spine pain.

Figure 3.

Bone scintigraphy showing high-grade focal uptake in the posterior segment of the 7^th left costal arch (blue arrows), in the posterior segment of the 7^th, 8^th, and 9^th right costal arches, (black arrows) and in the anterior segment of L4 (red arrow), indicating multiple metastatic implants of an advanced staging disease.

Figure 4.

Histological aspect of the lesion biopsy showing infiltrating nests with a carcinomatous characteristic with poorly differentiated glandular structures in the lower right corner (A) Immunohistochemistry with TTF-1 labeling showing diffuse positivity in neoplastic cells (B) and p63 labeling with nuclear positivity in about 10% of neoplastic cells (C), indicating immunophenotype of double glandular and squamous differentiation, compatible with a diagnosis of ASC.