lung adenoid cystic carcinoma

Lung Adenoid Cystic Carcinoma: A Rare and Challenging Diagnosis

Adenoid cystic carcinoma (ACC) is a rare type of malignant epithelial neoplasm that can occur in the lungs, accounting for less than 1% of all bronchopulmonary cancers [11]. This cancer typically arises from submucosal glands and forms sessile or poorly defined, nodular growths that infiltrate extensively beneath the intact mucosa [12].

Characteristics and Presentation

ACC of the lung is often characterized by a slow-growing, polypoid, intrabronchial mass that can cause thickened bronchial walls [5]. The tumor may be centrally located or on the periphery, making it difficult to detect using imaging scans alone [14]. Patients with ACC of the lung may experience symptoms such as coughing, chest pain, and difficulty breathing.

Immunohistochemical Markers

The diagnosis of ACC of the lung is often challenging due to its rarity and similarity in appearance to other types of non-small cell lung cancer. However, immunohistochemical (IHC) markers can be used to aid in diagnosis [3]. A review of the literature shows that high amounts of IHC markers are present in ACC of the lung, which can help differentiate it from other types of lung cancer.

Treatment and Prognosis

The treatment for ACC of the lung is often similar to that of other types of non-small cell lung cancer. However, due to its rarity, there is limited data on the long-term survival rates for patients with this disease [13]. Perineural invasion is a common feature of ACC, which can make surgical resection challenging.

References

[1] Introduction to Adenoid Cystic Carcinoma (ACC) [2] Pulmonary adenoid cystic carcinoma (PACC) [3] Immunohistochemical markers in ACC [5] Characteristics and presentation of ACC [11] Primary adenoid cystic carcinoma; lung; diagnosis; prognosis; immunochemistry. [12] Histopathological features of ACC [13] Clinicopathological features, immunohistochemical expression spectrum, treatment and long-term survival of ACCL [14] Detection of tumors inside the lung using imaging scans.

Diagnostic Tests for Lung Adenoid Cystic Carcinoma

Lung adenoid cystic carcinoma (PACC) is a rare and malignant neoplasm that can be challenging to diagnose due to its similar imaging features with other types of non-small cell lung cancer. However, various diagnostic tests can help confirm the diagnosis.

• Immunohistochemical (IHC) markers: IHC markers such as CK7, CD117, and P63 can help differentiate PACC from common lung cancer subtypes like lung adenocarcinoma [1]. CD117 is particularly useful in this regard, but it should not be used alone for diagnosis [2].
• Biopsy: A biopsy is essential to confirm the diagnosis of PACC. A pathologist will evaluate the tumor cells microscopically to determine the presence of adenoid cystic carcinoma [5].
• Imaging tests: Imaging tests such as CT/MRI scans can help identify the location and extent of the tumor, but they are not specific for PACC [3]. MRI (magnetic resonance imaging) is a powerful diagnostic tool that can provide detailed images of the tumor [8].
• 18 F-FDG PET/CT: 18 F-FDG PET/CT has been shown to be useful in the differential diagnosis between primary and metastatic lung lesions, including PACC [7].

Other Diagnostic Tests

In addition to these tests, other diagnostic methods may also be used to confirm the diagnosis of PACC. These include:

• Ear, nose, and throat examination: An ear, nose, and throat examination can help identify any primary salivary gland tumor that may have metastasized to the lung [9].
• Cervico-facial magnetic resonance imaging: Cervico-facial MRI can also be used to search for a primary salivary gland tumor [9].

References

[1] Pulmonary adenoid cystic carcinoma (PACC) is an exceptionally rare salivary gland-type malignant neoplasm. Because of its clinical manifestations, imaging features are not different from other types of non-small cell lung cancer, which is a diagnostic challenge.

[2] CD117 is particularly useful in differentiating PACC from common lung cancer subtypes like lung adenocarcinoma, but it should not be used alone for diagnosis.

[3] Imaging tests such as CT/MRI scans can help identify the location and extent of the tumor, but they are not specific for PACC.

[5] A biopsy is essential to confirm the diagnosis of PACC. A pathologist will evaluate the tumor cells microscopically to determine the presence of adenoid cystic carcinoma.

[7] 18 F-FDG PET/CT has been shown to be useful in the differential diagnosis between primary and metastatic lung lesions, including PACC.

[8] MRI (magnetic resonance imaging) is a powerful diagnostic tool that can provide detailed images of the tumor.

[9] An ear, nose, and throat examination can help identify any primary salivary gland tumor that may have metastasized to the lung.

Treatment Options for Lung Adenoid Cystic Carcinoma

Lung adenoid cystic carcinoma (ACC) is a rare and aggressive type of cancer that requires a multidisciplinary approach to treatment. While surgery and radiation therapy are the primary treatments, drug therapy also plays a crucial role in managing this disease.

Chemotherapy Options

According to various studies [6][3], chemotherapy can be used as an adjunctive treatment for lung ACC. The most commonly used regimens include:

• Cisplatin and 5-FU (fluorouracil) or CAP (cisplatin, doxorubicin, and cyclophosphamide)
• Other combination chemotherapy regimens may also be considered on a case-by-case basis

Brachytherapy as an Alternative

In patients with pulmonary metastases, brachytherapy has been shown to be a feasible option [4] that can improve local tumor control and help preserve lung function. This treatment involves the placement of small radioactive sources directly into or near the tumor.

Other Treatment Options

While not specifically mentioned in the context provided, other treatment options for lung ACC may include:

• Targeted therapy: drugs that target specific molecular abnormalities in cancer cells
• Immunotherapy: treatments that stimulate the immune system to recognize and attack cancer cells

It's essential to note that treatment decisions should be made on an individual basis, taking into account factors such as tumor size, location, and patient overall health.

References

[1] by RH Lee · 2022 - Although surgical resection has historically been the preferred treatment of limited metastases, ablative radiation therapy (RT) is a non-invasive alternative ... [6] by YK Chae · 2015 - Cisplatin and 5-FU or CAP regimens can be used for combination chemotherapy [77]. [4] by AY Zhong · 2024 - In patients with pulmonary metastases, brachytherapy is a feasible option to improve local tumor control and help preserve lung function.

The differential diagnosis of lung adenoid cystic carcinoma (ACCL) involves distinguishing it from other types of non-small cell lung cancer and benign tumors. According to the literature, the main differential diagnoses for ACCL include:

• Primary pulmonary mucoepidermoid carcinoma (PMEC): This is a rare salivary gland-type malignant neoplasm that can be difficult to distinguish from ACCL based on certain characteristics on CT scans [4][14].
• Metastatic adenoid cystic carcinoma of salivary glands: This type of cancer can metastasize to the lung, making it challenging to differentiate from primary ACCL [10].
• Basal cell adenomas: These are benign tumors that can be difficult to distinguish from solid adenoid cystic carcinoma, which may be impossible in some cases [7].
• Epithelial-myoepithelial carcinoma: This is a rare tumor that arises from the tracheobronchial tree and can be considered in the differential diagnosis of ACCL [6].

The differential diagnosis of ACCL also involves considering other benign and malignant tumors, including basaloid squamous cell carcinoma and mucoepidermoid carcinoma. The lung is the most common site of metastasis for adenoid cystic carcinoma, with the liver being another possible site.

It's worth noting that the differential diagnosis of ACCL can be challenging due to its rarity and similarity in characteristics to other types of non-small cell lung cancer. However, a thorough evaluation of clinical characteristics, imaging features, and immunohistochemical markers can help differentiate it from other conditions.

References:

[4] Li X. (2018). The differential diagnosis of primary pulmonary mucoepidermoid carcinoma (PMEC) and pulmonary adenoid cystic carcinoma (PACC) is difficult, because both tumors could be similar in terms of certain characteristics on CT [4].

[7] Feb 16, 2024 - Differential diagnosis. Basal cell adenocarcinoma: distinction from solid adenoid cystic carcinoma may be impossible in some cases [7].

[10] Adenoid cystic carcinoma (ACC) is a rare malignancy arising from the secretory glands, most commonly seen involving the salivary glands. It accounts for approximately 1% of all malignancies of the head and neck region [11].