Fetal adenocarcinoma | |
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Other names | Well differentiated fetal adenocarcinoma, high-grade fetal adenocarcinoma, pulmonary adenocarcinoma of fetal type, and pulmonary endodermal tumour resembling fetal lung. [1] |
Micrograph showing fetal adenocarcinoma. H&E stain. |
Fetal adenocarcinoma (FA) of the lung is a rare subtype of pulmonary adenocarcinoma that exhibits tissue architecture and cell characteristics that resemble fetal lung tissue upon microscopic examination. It is currently considered a variant of solid adenocarcinoma with mucin production. [1]
FA can produce repeated hemoptysis, possibly related to cavitation of the tumor. [2]
Other presenting symptoms described have included: flu-like syndrome with cough and fever, [3]
Due to its rarity, little is known of the genetics of FA. [4]
One small series of 6 cases showed that MDM2 protein was expressed in 5 of them (83%), and p53 protein was overexpressed in 50%. [5] However, a larger series of 12 cases revealed no p53 gene mutations. [4]
The details of the histogenesis of FA remain unknown and highly debated. [6] Adenocarcinomas are most often highly heterogeneous peripheral tumors, [7] and are thought to arise from malignant transformation of primitive cells that can exhibit differentiation characteristics of Club cells, Type II pneumocytes, bronchiolar surface cells, bronchial gland cells, or goblet cells. [8] [9]
Most FA's are well or moderately differentiated tumors, although high-grade, poorly differentiated variants have been described. [1] [10] [11] Tissue resembling FA can also be found admixed with a component made up of primitive blastoma-like cells. In such cases, these biphasic tumors are classified as a form of pulmonary blastoma because the presence of the blastomatous cells dramatically worsens the prognosis. [11] [12]
FA can occur in combination with other forms of lung cancer, particularly other variants of adenocarcinoma. [1] There also seems to be an association with clear cell lung cancer variants. [13] A case of combined small cell lung carcinoma featuring components of FA and cells resembling those from carcinoid tumor has been reported, illustrating the unique complexity and heterogeneity of divergent histogenesis and cell differentiation in lung cancer. [14]
FA is an epithelial tumor whose cells and architecture resemble that of fetal lung tissues in the pseudoglandular stage of development (which occurs at about 10–16 weeks gestation in the human), [6] with complex glandular structures and morules with cell nuclei that appear clear due to the accumulation of biotin. [15]
While FA can be diagnosed via biopsy, bronchial brushings, and immunocytochemistry, [16] examination of the whole tumor is required to rule out biphasic pulmonary blastoma, a mixed tumor of higher aggressiveness, wherein FA occurs admixed with primitive blastoma cells. [6]
Although it is not normally considered a fast-growing malignant neoplasm, FA can exhibit high uptake on FDG-PET scanning. [17]
Identification of aberrant nuclear localization of a mutated protein product of the beta-catenin gene has been proposed as a diagnostic tool for FA. [18]
Although FA's usually occur as nodules or masses, they can sometimes present as a multifocal disease. [19]
Because of its extreme rarity, there have been no controlled clinical trials of treatment regimens for FA and, as a result, there are no evidence-based treatment guidelines. [6] Complete surgical resection is the treatment of choice in FA, as it is in nearly all forms of lung cancer. [20]
Anecdotal reports suggest that FA is rarely highly sensitive to cytotoxic drugs [20] or radiation. [2] Case reports suggest that chemotherapy with UFT may be useful in FA. [13]
The prognosis of patients with FA as a whole is considered to be better than that of most other forms of non-small cell carcinoma, including biphasic pulmonary blastoma. [21] [22]
FA is a rare tumor, with a relative incidence estimated to be no more than 0.5% of all lung cancers. [2] [23] [24] [6]
FA is exceptionally rare in children, with only a handful of cases reported to date, [25] However, several case reports have involved FA's in pregnant women or the early postnatal period. [2] [24]
Adenocarcinoma is a type of cancerous tumor that can occur in several parts of the body. It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or both. Adenocarcinomas are part of the larger grouping of carcinomas, but are also sometimes called by more precise terms omitting the word, where these exist. Thus invasive ductal carcinoma, the most common form of breast cancer, is adenocarcinoma but does not use the term in its name—however, esophageal adenocarcinoma does to distinguish it from the other common type of esophageal cancer, esophageal squamous cell carcinoma. Several of the most common forms of cancer are adenocarcinomas, and the various sorts of adenocarcinoma vary greatly in all their aspects, so that few useful generalizations can be made about them.
Pleuropulmonary blastoma (PPB) is a rare cancer originating in the lung or pleural cavity. It occurs most often in infants and young children but also has been reported in adults. In a retrospective review of 204 children with lung tumors, pleuropulmonary blastoma and carcinoid tumor were the most common primary tumors. Pleuropulmonary blastoma is regarded as malignant. The male:female ratio is approximately one.
A blastoma is a type of cancer, more common in children, that is caused by malignancies in precursor cells, often called blasts. Examples are nephroblastoma, medulloblastoma, and retinoblastoma. The suffix -blastoma is used to imply a tumor of primitive, incompletely differentiated cells, e.g., chondroblastoma is composed of cells resembling the precursor of chondrocytes.
Adenocarcinoma in situ (AIS) of the lung —previously included in the category of "bronchioloalveolar carcinoma" (BAC)—is a subtype of lung adenocarcinoma. It tends to arise in the distal bronchioles or alveoli and is defined by a non-invasive growth pattern. This small solitary tumor exhibits pure alveolar distribution and lacks any invasion of the surrounding normal lung. If completely removed by surgery, the prognosis is excellent with up to 100% 5-year survival.
Tumor protein p63, typically referred to as p63, also known as transformation-related protein 63 is a protein that in humans is encoded by the TP63 gene.
Signet ring cell carcinoma (SRCC) is a rare form of highly malignant adenocarcinoma that produces mucin. It is an epithelial malignancy characterized by the histologic appearance of signet ring cells.
NK2 homeobox 1 (NKX2-1), also known as thyroid transcription factor 1 (TTF-1), is a protein which in humans is encoded by the NKX2-1 gene.
Combined small cell lung carcinoma is a form of multiphasic lung cancer that is diagnosed by a pathologist when a malignant tumor, arising from transformed cells originating in lung tissue, contains a component of;small cell lung carcinoma (SCLC), admixed with one components of any histological variant of non-small cell lung carcinoma (NSCLC) in any relative proportion.
Large cell lung carcinoma with rhabdoid phenotype (LCLC-RP) is a rare histological form of lung cancer, currently classified as a variant of large cell lung carcinoma (LCLC). In order for a LCLC to be subclassified as the rhabdoid phenotype variant, at least 10% of the malignant tumor cells must contain distinctive structures composed of tangled intermediate filaments that displace the cell nucleus outward toward the cell membrane. The whorled eosinophilic inclusions in LCLC-RP cells give it a microscopic resemblance to malignant cells found in rhabdomyosarcoma (RMS), a rare neoplasm arising from transformed skeletal muscle. Despite their microscopic similarities, LCLC-RP is not associated with rhabdomyosarcoma.
Epithelial-myoepithelial carcinoma of the lung is a very rare histologic form of malignant epithelial neoplasm ("carcinoma") arising from lung tissue.
Targeted therapy of lung cancer refers to using agents specifically designed to selectively target molecular pathways responsible for, or that substantially drive, the malignant phenotype of lung cancer cells, and as a consequence of this (relative) selectivity, cause fewer toxic effects on normal cells.
Mucinous cystadenocarcinoma of the lung (MCACL) is a very rare malignant mucus-producing neoplasm arising from the uncontrolled growth of transformed epithelial cells originating in lung tissue.
Sarcomatoid carcinoma, sometimes referred to as pleomorphic carcinoma, is a relatively uncommon form of cancer whose malignant cells have histological, cytological, or molecular properties of both epithelial tumors ("carcinoma") and mesenchymal tumors ("sarcoma"). It is believed that sarcomatoid carcinomas develop from more common forms of epithelial tumors.
Acinar adenocarcinoma is a histological subtype of gland-forming cancer that is diagnosed when cuboidal and/or columnar shaped malignant cells in the neoplastic tissue form acini and tubules. It is a common form of cancer occurring in the lung and prostate gland.
Sarcomatoid carcinoma of the lung is a term that encompasses five distinct histological subtypes of lung cancer, including (1) pleomorphic carcinoma, (2) spindle cell carcinoma, (3) giant cell carcinoma, (4) carcinosarcoma, or (5) pulmonary blastoma.
Giant-cell carcinoma of the lung (GCCL) is a rare histological form of large-cell lung carcinoma, a subtype of undifferentiated lung cancer, traditionally classified within the non-small-cell lung carcinomas (NSCLC).
Adenosquamous lung carcinoma (AdSqLC) is a biphasic malignant tumor arising from lung tissue that is composed of at least 10% by volume each of squamous cell carcinoma (SqCC) and adenocarcinoma (AdC) cells.
Salivary gland–like carcinomas of the lung generally refers a class of rare cancers that arise from the uncontrolled cell division (mitosis) of mutated cancer stem cells in lung tissue. They take their name partly from the appearance of their abnormal cells, whose structure and features closely resemble those of cancers that form in the major salivary glands of the head and neck. Carcinoma is a term for malignant neoplasms derived from cells of epithelial lineage, and/or that exhibit cytological or tissue architectural features characteristically found in epithelial cells.
Basaloid squamous cell carcinoma (Bas-SqCC) is an uncommon histological variant of lung cancer composed of cells exhibiting cytological and tissue architectural features of both squamous cell lung carcinoma and basal cell carcinoma.
Basaloid large cell carcinoma of the lung, is a rare histological variant of lung cancer featuring certain distinctive cytological, tissue architectural, and immunohistochemical characteristics and clinical behavior.