Carcinoid tumorlets simulate pulmonary metastases in women with breast cancer

Pulmonary Carcinoid Tumorlet in the Explanted Lungs for Lung Transplantation: A Case Series of 15 Patients

BACKGROUND

Pulmonary carcinoid tumorlet (PCT) is defined as small proliferation of neuroendocrine cells that invade the adjacent basement membrane. It is often associated with chronic pulmonary inflammatory processes. However, the characteristics of PCT in end-stage lung diseases remain unclear.

METHODS

We conducted a retrospective cohort study of the explanted lungs after transplantation at our institution between January 1999 and October 2020. Patients who underwent re-transplantation were excluded.

RESULTS

Pulmonary carcinoid tumorlet was incidentally discovered in the explanted lungs from 15 patients (1.1%) out of 1367 lung transplants performed during the study period. Nine patients (60.0 %) were women, with a median age of 59 years (IQR: 57-62) at transplant. Underlying pulmonary indications for lung transplantation were chronic obstructive pulmonary disease (9/15, 60.0%), interstitial lung disease (2/15, 13.0%), pulmonary vascular disease (2/15, 13.0%), alpha-1 antitrypsin deficiency (1/15, 7.0%), and bronchiectasis (1/15, 7.0%). Of the patients who underwent bilateral lung transplantation (13/15, 86.7%), PCT was found in the right lung in 10 patients (10/13, 76.9%). Thirteen patients had one lesion, 1 patient had 2 lesions and 1 patient had multiple lesions.

CONCLUSION

Our study shows that PCT is generally uncommon, but when it occurs, it occurs more frequently on the right side and in female patients with end-stage pulmonary disease. Chronic obstructive pulmonary disease may be a predisposing factor for developing PCT.

Metastatic breast cancer simulating well-differentiated neuroendocrine neoplasms of visceral organs

A series of metastatic breast carcinoma (MBC) mimicking visceral well-differentiated neuroendocrine neoplasms has not previously been reported. We identified 5 consultation cases originally submitted as neuroendocrine neoplasms in women but that were found to be MBC on subsequent review. All 5 neoplasms demonstrated nested architecture and relatively uniform nuclei. Four patients had a known history of breast cancer (remote in 3 and concurrent in 1), but the metastases (3 liver, 1 lung) labeled for chromogranin and/or synaptophysin, prompting misdiagnosis as neuroendocrine neoplasm. In a fifth case, a liver metastasis in a patient with a known pancreatic endocrine neoplasm was originally thought to be of pancreatic origin; an occult concurrent primary breast cancer (PBC) was subsequently identified as the source. On further immunohistochemistry (IHC), all metastases evaluated were diffusely, strongly positive for estrogen receptor (5/5 cases) and GATA3 (4/4 cases). Three patients had previously received ineffective treatment for neuroendocrine carcinoma. Based on the consultation diagnosis, all 4 patients with follow-up received hormone therapy, which was effective in 3. In a separate tissue microarray cohort of paired PBCs and hematogenous MBCs, chromogranin and/or synaptophysin IHC labeling was typically negative and increased from the PBC to the MBC in only 5% of cases. In conclusion, although neuroendocrine differentiation is uncommon in breast cancer and does not commonly increase in metastases, MBC with neuroendocrine differentiation should be considered in patients with visceral neuroendocrine neoplasms of unknown primary site. Diffuse IHC labeling for estrogen receptor and GATA3 helps establish the correct diagnosis.

Cardiothoracic manifestations of neuroendocrine tumours

Cardiothoracic neuroendocrine tumour (NET) manifestations encompass a vast disease spectrum. Pulmonary neuroendocrine tumours represent a range of tumour grade and differentiation characteristics from pre-malignant diffuse neuroendocrine cell hyperplasia, well-differentiated, low-grade carcinoid tumours with excellent outcomes, through to high-grade small-cell lung carcinoma and large-cell neuroendocrine carcinoma with poor prognoses. Rarer thymic NETs represent a similarly wide neoplastic spectrum. Cardiac carcinoid is a paraneoplastic manifestation of the carcinoid syndrome and often the cause of mortality in NETs with hepatic metastases. Cardiothoracic NET manifestations are reviewed herein from a radiologists' perspective, discussing the diverse clinical presentations, spectrum of neoplastic and paraneoplastic manifestations, imaging features and treatment options.

The spectrum of changes in adults with multifocal pulmonary neuroendocrine proliferations: what is the minimum set of pathologic criteria to diagnose DIPNECH?

Diffuse idiopathic neuroendocrine cell hyperplasia (DIPNECH) can be difficult to diagnose in resections for lung tumors and other conditions, as variable diagnostic criteria and definitions of "diffuse" and/or "idiopathic" have been used in the literature. We reviewed 70 consecutive lung wedge biopsies and resection specimens with multifocal neuroendocrine cell proliferations (NEP) including neuroendocrine cell hyperplasia (NECH) and/or carcinoid tumorlets to identify pathologic findings significantly associated with neuroendocrine neoplasms. The presence of pathologic changes other than NEP (eg, interstitial fibrosis, bronchiectasis, others) and the number of tumorlets were recorded to identify "idiopathic NEP." Cases were classified into 4 groups: A: NECH only, B: >1 tumorlet without NECH, C: NECH + 2 tumorlets, and D: NECH + >2 tumorlets. Proportions of neuroendocrine neoplasms and presence/absence of pathologic changes other than NEP were compared by group with χ(2) statistics. Carcinoids were seen in 8 (22.8%) of 35 and in 21 (72.4%) of 29 groups B and D cases, respectively. Of the 21 group D carcinoids, 18 (85.7%) lacked other associated pathologic changes, and the incidence of these tumors in this group was significantly higher (P < .001) than in group B. Three high-grade neuroendocrine carcinomas were seen, 1 each in groups A to C. Because group D cases had a significantly higher proportion of carcinoid tumors and a significant lack of association with conditions that could result in secondary NECH, the presence of multifocal NECH combined with 3 or more carcinoid tumorlets is proposed as minimum pathologic criteria for the diagnosis of DIPNECH.

Spectrum of pulmonary neuroendocrine proliferations and neoplasms

Neuroendocrine neoplasms are ubiquitous tumors found throughout the body, most commonly in the gastrointestinal tract followed by the thorax. Neuroendocrine cells occur normally in the bronchial and bronchiolar epithelium and may be solitary or may occur in clusters. Although neuroendocrine cell proliferations may be found in association with chronic lung disease, a broad range of neuroendocrine proliferations and neoplasms may occur and exhibit variable biologic behavior. Diffuse idiopathic neuroendocrine cell hyperplasia (DIPNECH) is a diffuse idiopathic form of neuroendocrine cell hyperplasia and is considered a preinvasive lesion that may give rise to carcinoid tumors. Patients with DIPNECH are typically older women who may be asymptomatic or may present with chronic respiratory symptoms. DIPNECH manifests as multifocal bilateral pulmonary micronodules on expiratory high-resolution computed tomographic (CT) images; the air trapping is secondary to constrictive bronchiolitis. Carcinoid tumors are low-grade malignant neoplasms that typically affect symptomatic children and young adults. Carcinoids manifest as well-defined pulmonary nodules or masses that are often closely related to central bronchi. They may exhibit intrinsic calcification and contrast material enhancement at CT, and patients with carcinoids may have postobstructive atelectasis and pneumonia. Although typical carcinoids are indolent neoplasms and patients have a good prognosis, atypical carcinoids are aggressive malignancies with a propensity for metastasis. Both are optimally treated with complete surgical excision. Large cell neuroendocrine carcinoma and small cell lung cancer are highly aggressive neuroendocrine malignancies that usually affect elderly smokers. These tumors manifest with large peripheral or central pulmonary masses. Local invasion, intrathoracic lymphadenopathy, and distant metastases are frequent at presentation. As a result, affected patients may not be candidates for surgical resection, are often treated with chemotherapy with or without radiation, and have a poor prognosis.

Association of carcinoid tumor and low grade glioma

Background

Lung carcinoid tumor and low grade glioma are two uncommon malignancies.

Patients and methods

We report the case of 24-year-old man who presented with respiratory disease. Imaging investigations showed a right lung tumor and histological analysis confirmed a typical carcinoid tumor. As part of initial staging, brain MRI revealed an asymptomatic right frontal lesion. First, a right pulmonary lobectomy was performed without adjuvant treatment. In second time, brain tumorectomy was performed. Histological examination confirmed the diagnosis of low grade glioma (LGG). The patient remained in complete remission 2.5 years after the initial diagnosis.

Results

This is the first case reporting the association between LGG and lung carcinoid tumor, while no association between LGG and a systemic tumor have been published to date. Association of lung carcinoid tumor with other malignant diseases has been reported but remained uncommon. Only minimal data support a potential molecular common origin.

Conclusion

This exceptional association may be fortuitous. However, their concomitant diagnoses suggest a potential association between both rare diseases. A genetic susceptibility remains possible.

Neuroendocrine tumors of the lung: an update

CONTEXT

The 2004 World Health Organization (WHO) classification recognizes 4 major types of lung neuroendocrine tumors: typical carcinoid, atypical carcinoid, small cell lung cancer, and large cell neuroendocrine carcinoma. Markedly different prognostic implications and treatment paradigms for these tumors underscore the importance of accurate pathologic diagnosis.

OBJECTIVE

To detail the clinical and pathologic features of lung neuroendocrine tumors, with emphasis on diagnostic criteria, differential diagnoses, and application of immunohistochemistry. The emerging evidence for the utility of Ki-67 (MIB1) in the diagnosis of lung neuroendocrine tumors, particularly in small biopsy and cytology, is emphasized.

DATA SOURCES

The 2004 WHO classification, other published literature, and primary material from the author's institution.

CONCLUSIONS

The current WHO classification of neuroendocrine tumors is based on morphologic features in combination with precisely defined mitotic rate and absence or presence of necrosis. Ki-67 (MIB1) is emerging as a useful ancillary tool in the diagnosis of these tumors. Continued research efforts are needed to identify additional immunohistochemical and molecular biomarkers that can serve as ancillary diagnostic tools and as potential therapeutic targets for these diseases.

Immunohistochemical expression of estrogen and progesterone receptors in primary pulmonary neuroendocrine tumors

CONTEXT

Lung and breast carcinomas are among the most prevalent cancers. Advances in cancer therapies can provide survival benefit and be potentially curative, even in metastatic disease. Due to the high prevalence of these carcinomas, it is not unusual to encounter lung nodule(s) in a patient with breast carcinoma, and distinguishing between primary and metastatic disease is critical for management/treatment. Occasionally neuroendocrine differentiation is present in breast carcinoma, making its distinction from pulmonary/nonpulmonary neuroendocrine tumors in the lung difficult.

OBJECTIVE

To assess estrogen and progesterone receptor expression in the entire spectrum of pulmonary neuroendocrine tumors.

DESIGN

Seventy-one neuroendocrine neoplasms including typical carcinoids (42), atypical carcinoids (7), small cell carcinomas (14), large cell neuroendocrine carcinomas (2), and combined small cell carcinomas (6) were evaluated for estrogen and progesterone receptors. Mammary and non-small cell lung carcinomas were also stained for comparison.

RESULTS

The entire spectrum of neuroendocrine neoplasms demonstrated focal to diffuse estrogen (typical carcinoid, 23; atypical carcinoid, 6; small cell carcinoma, 8; large cell neuroendocrine carcinoma, 2; combined small cell carcinoma, 4) and progesterone (typical carcinoid, 11; atypical carcinoid, 2; small cell carcinoma, 7; large cell neuroendocrine carcinoma, 0; combined small cell carcinoma, 2) expression. There was no correlation between sex and estrogen/progesterone status. Estrogen and progesterone staining were also noted in endothelial cells. Relative to neuroendocrine carcinomas, mammary carcinomas expressed estrogen and progesterone more frequently. Non-small cell carcinomas had greater and similar immunoreactivity for estrogen and progesterone, respectively.

CONCLUSIONS

Although estrogen and progesterone receptor staining is frequently associated with breast and gynecologic primaries, it can also be observed in "nontarget" organs. Therefore, presence of estrogen and/or progesterone expression in neuroendocrine tumors involving the lung should not exclude a primary pulmonary neoplasm.

[A 74-year-old female patient with histologically proven carcinoid of the lungs and pulmonary mosaic pattern]

Diffuse idiopathic neuroendocrine cell hyperplasia (DIPNECH) can be idiopathic or reactive to chronic airway disease, then termed pulmonary neuroendocrine cell hyperplasia (PNECH). DIPNECH can be complicated by obliterative bronchiolitis and is presumably often misdiagnosed because the clinical symptoms are unspecific, the entity is relatively unknown and high-resolution computed tomography (HRCT) in inspiration and expiration is necessary for the diagnosis. However, the HRCT findings of air-trapping in combination with nodules are very characteristic and should raise suspicion of this entity. DIPNECH is thought to be a precursor of tumorlets and carcinoids and usually runs a benign course. The diagnosis is confirmed by histology.

Significance of multiple carcinoid tumors and tumorlets in surgical lung specimens: analysis of 28 patients

BACKGROUND

The clinical significance of multiple carcinoid tumorlets in surgical lung specimens has not been systematically analyzed. We reviewed our experience to determine the range of clinical circumstances associated with this finding.

METHODS

We reviewed clinical records, available imaging, and pathology materials from patients evaluated at Mayo Clinic Rochester (from 1987 to 2000) with two or more carcinoid tumors or tumorlets in lung specimens.

RESULTS

Twenty-eight of 294 patients with a diagnosis of carcinoid tumor or tumorlet had two or more lesions. Twenty-six patients (93%) were women; mean age was 65 years. Patients were categorized into three groups: multiple nodules (n = 17), solitary lung nodules on preoperative imaging (n = 7), and airflow limitation (n = 4). Approximately half of patients with multiple nodules had respiratory complaints; two patients had Cushing syndrome. Ten patients (58.8%) were suspected of having pulmonary metastases, including 7 patients with previously diagnosed malignancies. Intrathoracic lymph node metastases were present in three patients, none of whom had recurrent disease. One patient had a carcinoid tumor resected 8 years later. Extrathoracic metastases developed in another patient 3 years after presentation, and the patient was alive with disease 2 years later. Only one patient with airflow limitation had a syndrome resembling diffuse idiopathic pulmonary neuroendocrine cell hyperplasia.

CONCLUSIONS

Our series represents the largest compilation of multiple carcinoid tumors or tumorlets. Our analysis reveals that multiple carcinoid tumors or tumorlets occur most commonly in patients with multiple nodules resembling metastatic disease. Significant airflow limitation is rare. Long-term survival is excellent, although patients have persistent disease.