1. A diagnostic challenge: an incidental lung nodule in a 48-year-old nonsmoker
Blake Christianson1, Smeet Patel MD1, Supriya Gupta MD1, Shikhar Vyas MD2, Helena Spartz MD, PhD2, Jayanth Keshavamurthy MD2
1Department of Radiology, 2Department of Pathology, Medical College of Georgia at Augusta University, Augusta GA
INTRODUCTION
Subsequently, contrast-enhanced CT of the chest was performed which showed a 1.8 cm, mildly spiculated right lower lobe pulmonary nodule with punctate internal calcification and enhancement (Figure 1A-1C). Succeeding PET/CT was without evidence of increased metabolic activity at the site of right lower lobe lung nodule (Figure 1D).
DISCUSSION
Adenocarcinoma is a frequent non-small carcinoma of the lung, however a colloid subtype is a rare entity. This tumor exhibits a pattern and degree of differentiation that is similar to mucinous adenocarcinoma of the gastrointestinal tract.
Colloid adenocarcinoma are extremely rare subtype of lung adenocarcinoma, and is characterized by pools of mucin-containing spaces with scant epithelium [1, 2]. Grossly, these tumors are well-circumscribed, intrapulmonary, lobulated and soft, with a central cavity filled with translucent mucus, ranging in size from 1 cm to greater than 10 cm. The presence of gelatinous, mucinous material is noted in the gross description of nearly all cases, however a well-defined cyst wall is not usually seen.
In general, colloid adenocarcinoma of the lung present incidentally in an asymptomatic patient. If symptomatic, the patient can experiences hemoptysis and cough as evident in our case. These patients can also present with infections of the lung or respiratory symptoms as the lesion slowly enlarges. Pulmonary function tests are often normal due to the localized nature of the mass [1,2]. A B C D
LEARNING OBJECTIVES
Identify radiology and pathology features of colloid carcinoma.
Incorporate rad-path correlation to diagnose a rare or unfamiliar disease.
CASE INFORMATION
Figure 1: Non-contrast axial CT (A,B) demonstrating a 1.8cm spiculated lung nodule (A) with mild enhancement upon contrast administration (C), and an SUV value of 3 on PET/CT (D)
A 43-year old presented to her urologist with bilateral flank pain. She complained of worsening exertional dyspnea over the last several months with an associated weight gain, night sweats, and intermittent scant hemoptysis.
Patient underwent Computed Tomography (CT) scan of the abdomen and pelvis which showed bilateral non-obstructing renal stones and an incidental 1.8 x 1.7 cm nodular opacity in the right lower lobe, which was not present on a previous scan 1 year prior.
Surgical wedge resection was performed and specimen sent to pathology.
CONCLUSION
Colloid adenocarcinoma poses a diagnostic challenge due to its bland radiologic findings. CT imaging is most sensitive and demonstrates ill-defined, low attenuating, cavitary nodules with wall and septal enhancement and ground glass opacities.
Histologically, lesions are characterized by pools of mucin-containing spaces with scant epithelium. Complete surgical resection of the neoplasm with wide margins is the first-line treatment.
Figure 2: Pathology demonstrated a cystic tumor filled with grayish gelatinous mucin (A) with alveolar walls focally lined by mucinous epithelium (B)
On histology, extensive areas of mucin deposition were noted, with distension and destruction of alveolar walls. While no cystic wall was visualized, the tumor demonstrated cyst-like appearance filled with grayish mucin (Fig-2A). Areas in which the alveolar walls remain intact were focally lined by mucinous epithelium (Fig-2B). Findings were consistent with colloid adenocarcinoma.
REFERENCES
1. Brownlee, N.A., et al., Mucinous (Colloid) Adenocarcinoma of the Lung. Archives of Pathology & Laboratory Medicine, (1): p
2. Masai, K., et al., Clinicopathological features of colloid adenocarcinoma of the lung: A report of six cases. Journal of Surgical Oncology, (2): p