499

CASE REPORT
Suspected Aspergillus nodule histologically consistent withpulmonary nodular lymphoid hyperplasia : a case report
Shun Morizumi1, 2, Atsushi Morishita3, 4, Miho Nishiyama1, Kiyohide Takahashi1, Kenya Sumitomo1, Hiroyuki Hino3,Keishi Naruse5, Eiji Takeuchi6, Shoji Sakiyama3, and Tsutomu Shinohara1, 2Division of Internal Medicine, Japan Agricultural Cooperatives Kochi Hospital, Kochi, Japan, 2Department of Community Medicine for Respirology, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan, 3Division of Thoracic Surgery, National Hospital Organization Kochi Hospital, Kochi, Japan, 4Division of Surgery, National Hospital Organization Higashi Tokushima Medical Center,Tokushima, Japan, 5Division of Clinical Laboratory, National Hospital Organization Kochi Hospital, Kochi, Japan, 6Department of Clinical
Investigation, National Hospital Organization Kochi Hospital, Kochi, Japan
1

Abstract : Aspergillus nodules (AN) are an unusual form of chronic pulmonary aspergillosis. On the other hand,
pulmonary nodular lymphoid hyperplasia (PNLH) is classified as a reactive pulmonary lymphoproliferative disorder. A 65-year-old male was referred to our hospital due to a nodule in the left upper lobe. Histologically,a mixture of prominent lymphoid follicular formation, and hyaline necrosis were observed. Grocott staining
revealed morphological forms of Aspergillus spp. in the necrosis. The final clinical diagnosis was suspected AN
histologically consistent with PNLH. This case suggests that there may be PNLH cases in which local infection
with Aspergillus contributes to its pathophysiology. J. Med. Invest. 70 : 499-502, August, 2023
Keywords : Aspergillus nodule, pulmonary nodular lymphoid hyperplasia, bronchus-associated lymphoid tissue

INTRODUCTION
Aspergillus spp. resides in natural environments and can form
various lung lesions depending on the immune function of thehost and the presence or absence of underlying lung disease.
Chronic pulmonary aspergillosis (CPA) in immunocompetentpatients is usually triggered by infection in pre-existing cavitarylesions, but, in rare cases, isolated or multiple nodule(s) withoutcavitation occur in the patients without underlying lung disease.
This type of CPA is classified as an Aspergillus nodule (AN) andis often resected on suspicion of lung cancer (1). We report thefirst case of an isolated, provable AN that was histologically consistent with pulmonary nodular lymphoid hyperplasia (PNLH).

CASE REPORT
A 65-year-old asymptomatic male smoker (45 pack-years) was
referred to our hospital due to a solitary nodule with calcification in the left upper lobe detected during a medical check-up.
Computed tomography (CT) showed the nodule was an irregularshape, with spotty internal calcification and an indistinct surrounding ground-glass opacity (Fig. 1A-C). He had no history ofallergic diseases. Initial laboratory data were as follows : whiteblood cell count 6030 / μL (neutrophils, 63.4% ; eosinophils,0.3%) ; C-reactive protein 0.06 mg / dL ; sialyl Lewis X-1 38 (< 39)
U / mL ; CYFRA 21-1 1.0 (< 3.5) ng / mL ; pro-gastrin-releasing
peptide 54.4 (< 81) pg / mL ; Aspergillus galactomannan antigen
value 0.1 (> 0.5 cut-off index). An interferon-gamma releaseassay (IGRA), IgA antibody test against Mycobacterium avium
Received for publication November 7, 2022 ; accepted February 21,
2023.
Address correspondence and reprint requests to Tsutomu Shinohara,
MD, PhD. Department of Community Medicine for Respirology, Graduate School of Biomedical Sciences, Tokushima University, 3-18-15
Kuramoto-cho, Tokushima 770-8503, Japan and Fax : +81-88-8632186. E-mail : t-shinohara@kouseiren.ja-kochi.or.jp

complex glycopeptidolipid and Aspergillus-specific precipitating
antibody were negative. The other laboratory tests results areshown in Table1. The nodule had slightly increased in size
compared to CT images taken at another facility three years
earlier, which was thought to be a post-inflammatory change(Fig. 1D). No other lesions were observed on whole-body contrast-enhanced CT. The maximum standardized uptake value ofthe nodule measured by 18F-fluorodeoxyglucose (FDG) positronemission tomography (PET) was 1.1 (Fig. 1E), but two diagnostic radiologists at separate institutions considered the nodule
to be a primary lung cancer because of its slow growth andsurrounding ground-glass opacity. Although calcification within
pulmonary nodules is generally considered a positive finding forchronic inflammation, the negative IGRA result virtually ruledout pulmonary tuberculoma. Moreover, it was reported thatcalcification was detected on CT in 5.4% of primary lung cancers
and 9.1% when limited to adenocarcinomas (2). Therefore, we determined that the nodule was most likely lung cancer. However,bronchoscopic examination did not lead to a definitive diagnosis.
The patient agreed to a surgical biopsy to obtain an early andaccurate diagnosis and underwent video-assisted thoracoscopic
partial lung resection for suspected lung cancer. Histologically,a mixture of prominent lymphoid follicular formation, and hyaline necrosis in and around the airways with calcification wereobserved continuous with the bronchiole (Fig. 2A-C). Atrophic
germinal centers surrounded by an expanded mantle zone, polytypic plasmacytosis in the interfollicular space, and vascularproliferation in the follicles and interfollicular region were notobserved, suggesting that the lesion was not due to Castleman’s
disease (Fig. 2D-E). A few neutrophils were observed in thenecrosis, but there was no eosinophilic infiltration. No fibrouscapsule formation was observed. An immunocytochemical study
demonstrated tightly packed CD20-positive B-cells predominantly within follicles (Fig. 2F), and Bcl-2-positive lymphocytes
outlining the follicles (Fig. 2G), showing a reactive pattern witha mixed population of lymphocytes. These findings were compatible with PNLH. Interestingly, Grocott staining revealed septate
hyphae with acute-angle branching compatible with morpholog-

The Journal of Medical Investigation Vol. 70 2023

S. Morizumi, et al. PNLH related to Aspergillus infection

500Fig 1. Chest CT images. (A-C) A solitary nodule with calcification in the left upper lobe. (D) An image of the nodule taken atanother facility three years earlier. (E) 18F-FDG-PET/CT.

Table 1. Laboratory data
Hematology
RBC

507×104 / μL

Alb

4.5 g / dL

CRP

0.06 mg / dL

Hb17.0 / dL

HbA1c

WBC6030 / μL

BG

5.4%

Urinaly testgravity

1.022

pH

6.0103 mg / dLprotein(1+)

38 U / mL

glucose(-)

Neutrophils

63.4%

sialyl Lewis X-1

Lymphocytes

29.5%

CYFRA 21-1

1.0 ng / mL

urobilinogen

Eosinophils

0.3%

pro-gastrin-releasing peptide

54.4 pg / mLbilirubin(-)

Monocytes

6.1%

Rheumatoid factor

11 U / mL

ketones(-)

0.7%

Aspergillus galactomannan
antigen value

Basophils
Plt

21.0×104 / μL

Biochemistry

(+/-)

0.1

Immunology

AST

24 IU / L

IgG

727 mg / dL

ALT

37 IU / L

IgA

117 mg / gL

ALP

203 IU / L

IgM

52 mg / dL

LDH

193 IU / L

IgG4

36.7 mg / dLγGTP

72 IU / LT-Bil

0.78 mg / dL

Aspergillus-specificprecipitating antibody

negative

BUN

14.3 mg / dL

Creatinine

0.78 mg / dL

Interferon-gamma releaseassay (T-SPOT.TB)

negativeNa

139.0 mEq / LK

3.6 mEq / L

negative

TP

6.8 g / dL

IgA antibody test against
Mycobacterium avium
complex glycopeptidolipid

RBC : red blood cell, Hb : hemoglobin, WBC : white blood cell, Plt : platelet, AST : aspartate amino transferase, ALT : alanine
amino transferase, LDH : lactate dehydrogenase, γGTP : gamma-glutamyl transpeptidase, T-Bil : total bilirubin, BUN : blood urea
nitrogen, Na : sodium, K : potassium, TP : total protein, Alb : albumin, CRP : C-reactive protein, BG : blood glucose.

The Journal of Medical Investigation Vol. 70 August 2023

501

Fig 2. Histology of a biopsy specimen (A-E : hematoxylin and eosin staining, F-G : immunohistochemical staining,

H-I : Grocott staining, A-B : low-power field, C-D : medium-power field, E-I : high-power field). (A-C) A mixture of prominent
lymphoid follicular formation, and hyaline necrosis in and around the airways. (D-E) Lymphoid follicles and interfollicularregion (F) Tightly packed CD20-positive B-cells predominantly within reactive follicles. (G) Bcl-2-positive lymphocytes outlining
the follicles. (H-I) Septate hyphae with acute-angle branching compatible with morphological forms of Aspergillus spp.

ical forms of Aspergillus spp. in the necrosis (Fig. 2H-I) without
invasion into surrounding tissues. No neoplastic cells were
present in the resected specimen. A real-time polymerase chain
reaction test for Aspergillus spp. (BML, Inc., Tokyo, Japan) of theparaffin embedded tissue failed to detect the microorganism due
to insufficient DNA extraction. No antifungal medications wereadministered, and there has been no recurrence one and a halfyears after resection.

DISCUSSION AND CONCLUSIONS
Since identification of fungi detected in the nodule was not
successful, the possibility of infection with fungi with branching
septate hyphae other than Aspergillus, such as Trichosporon orMucor, could not be ruled out. However, pulmonary mucormycosis and trichosporonosis generally occur in immunocompromised patients and progress rapidly with tissue invasion if left
untreated (3, 4). Trichosporonosis usually presents with diffuse
consolidation or multiple patchy shadows (3). Mucormycosis
shows a variety of multiple shadows, and the reverse halo sign
is observed at initial imaging in the majority of patients (4). Ourpatient, without underlying disease, had a solitary slowly-growing nodule and filamentous fungi were detected in the nodule,suggesting CPA in an immunocompetent patient.
One or more nodules (< 3 cm), which do not usually cavitate,

are an unusual form of CPA and are defined as AN. Although
histological studies are inadequate, AN is not necessarily anindependent category and is thought to overlap with other typesof CPA. Central necrosis is frequent, but tissue invasion is notdemonstrated in AN (1). One-third of patients with AN havea single lesion, but most patients with AN, including thesepatients, complain of cough and / or dyspnea (5). The natural
history of AN has not been clarified, but non-resected cases withclinical symptoms, high Aspergillus-specific IgG antibody titers
or with Aspergillus detected in respiratory specimens are treatedwith antifungal agents. On the other hand, antifungal agentsare not usually administered in resected cases (5). Therefore,
postoperative treatment with antifungal agents was not given
to our patient.
PNLH is a rare benign localized lesion classified as a reactive
pulmonary lymphoproliferative disorder. PNLH is generally
found incidentally in asymptomatic adult patients by routine
chest radiograph or CT. Two-thirds of patients have solitary lesions, and most lesions are solid or subsolid and less than 3 cm indiameter (6). The differential diagnosis of PNLH includes lungcancer, metastatic tumor, and primary lymphoma, which canpresent with similar radiological findings and ultimately require
surgical biopsy. Histologically, it consists of a prominent proliferation of lymphoid tissue, including abundant follicles with agerminal center without infiltration by interfollicular cells. Theinterfollicular cells are composed of small lymphocytes and plas-

502

S. Morizumi, et al. PNLH related to Aspergillus infection

ma cells without cytologic atypia. As in this case, CD20-positive
B cells are abundant in lymphoid follicles, whereas germinalcenter B cells do not co-express Bcl-2. PNLH is regarded as anodular hyperplastic lesion of bronchus-associated lymphoidtissue (BALT) (7). Resection of the nodule(s) is the only treatment for patients with PNLH, and recurrence has not beenreported in resected cases (6). In fact, no recurrence has been
observed in our case. Recently, a case of PNLH presenting as
multiple subsolid nodules in both lungs was reported in which
all six foci were surgically resected (8). Even so, to the best of ourknowledge, there are no reports on the prognosis of non-resected
PNLH cases.
Although several cases of PNLH with autoimmune disease,histologically suspected as actinomyces infection, and historyof tuberculosis treatment have been reported, the details of its
etiology have not been fully elucidated (9-11). Chronic inflammatory conditions and various infectious diseases, including
pneumocystis infection, are known to induce BALT ectopically(12, 13). In addition, lymphoid follicles were observed in a resected specimen from a patient with allergic bronchopulmonary
aspergillosis (14). However, there are no reports of PNLH related
to Aspergillus spp. infection.
The detailed mechanism is unknown, but this case suggeststhat there may be PNLH cases in which local infection withAspergillus contributes to its pathophysiology. While the pathological presentations of chronic pulmonary aspergillosis arediverse, it can be sometimes difficult to detect Aspergillus spp. byhematoxylin and eosin staining alone. Further research into theinvolvement of pathogenic microorganisms in PNLH is needed.

CONFLICT OF INTEREST
The authors declare no competing interests.

ACKNOWLEDGEMENTSNone.

REFERENCES
1.

Denning DW, Cadranel J, Beigelman-Aubry C, Ader F,Chakrabarti A, Blot S, Ullmann AJ, Dimopoulos G, Lange
C ; European Society for Clinical Microbiology and Infectious Diseases and European Respiratory Society : Chronic
pulmonary aspergillosis : rationale and clinical guidelines
for diagnosis and management. Eur Respir J 47 : 45-68,

2016
Okimoto N, Asaoka N, Fujita K : Computed tomography oflung cancer : frequency and characteristics of calcification.
Intern Med 42 : 906-907, 2003
3. Toba S, Tokimatsu I, Kadota J : Tricosporonosis. Jpn J
Chest Dis 73 : 1057-1067, 2014 (in Japanese)
4. Agrawal R, Yeldandi A, Savas H, Parekh ND, Lombardi PJ,Hart EM : Pulmonary Mucormycosis : Risk Factors, Radiologic Findings, and Pathologic Correlation. Radiographics
40 : 656-666, 2020
5. Muldoon EG, Sharman A, Page I, Bishop P, Denning
DW : Aspergillus nodules ; another presentation of Chronic
Pulmonary Aspergillosis. BMC Pulm Med 16 : 123, 2016.
doi : 10.1186/s12890-016-0276-3
6. Fang L, Xu J, Wang L, He Z, Lv W, Hu J : Pulmonary nodular lymphoid hyperplasia : a rare benign disease with malignant mask. Ann Transl Med 7 : 43, 2019. doi : 10.21037/atm.2018.12.59
7. Yell M, Rosado FG : Pulmonary Nodular Lymphoid Hyperplasia. Arch Pathol Lab Med 143 : 1149-1153, 2019
8. Cha YJ, Moon DH, Park JH, Lee S, Choi JA, Kim TH,
Park CH : Pulmonary nodular lymphoid hyperplasia presenting as multifocal subsolid nodules : A case report andliterature review. Respir Med Case Rep 36 : 101581, 2022.
doi : 10.1016/j.rmcr.2022.101581
9. Song MK, Seol YM, Park YE, Kim YS, Lee MK, Lee CH,Jeong YJ : Pulmonary nodular lymphoid hyperplasia associated with Sjögren’s syndrome. Korean J Intern Med
22 : 192-196, 2007
10. Tanino A, Tsubata Y, Hamaguchi S, Sutani A, Nagase M,
Isobe T : Antibiotic-induced reduction of abnormal lungshadow in pulmonary nodular lymphoid hyperplasia. Respirol Case Rep 8 : e00522, 2020. doi : 10.1002/rcr2.522
11. Kuzyk PV, Savchyna MA, Gychka SG : Rare case of nodularlymphoid hyperplasia of left lung in the patient with previous pulmonary tuberculosis. Exp Oncol 40 : 332-335, 201812. Foo SY, Phipps S : Regulation of inducible BALT formationand contribution to immunity and pathology. Mucosal Immunol 3 : 537-544, 2010
13. Eddens T, Elsegeiny W, Garcia-Hernadez ML, Castillo P,
Trevejo-Nunez G, Serody K, Campfield BT, Khader SA,
Chen K, Rangel-Moreno J, Kolls JK : Pneumocystis-Driven
Inducible Bronchus-Associated Lymphoid Tissue Formation
Requires Th2 and Th17 Immunity. Cell Rep 18 : 3078-3090,
2017
14. Slavin RG, Gleich GJ, Hutcheson PS, Kephart GM, Knutsen
AP, Tsai CC : Localization of IgE to lung germinal lymphoidfollicles in a patient with allergic bronchopulmonary aspergillosis. J Allergy Clin Immunol 90 : 1006-1008, 1992

2.