Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is an interesting and clinically relevant case of gastrointestinal basidiobolomycosis with unusual hepatobiliary involvement in a young woman during the early postpartum period. The manuscript is generally well presented, the clinical course is clear, and the combination of clinical, radiological, histopathological, and mycological findings provides useful educational value, particularly for clinicians working in endemic regions.

The following points may help strengthen the manuscript:

1. Please provide some additional detail on how Basidiobolus ranarum was identified at the species level. It would be useful to indicate whether identification was based on conventional microscopic morphology alone or whether molecular or other confirmatory methods were also used.
2. The histopathological findings are central to the diagnosis. If an appropriate image is available, the authors may wish to consider including a representative histopathology figure showing the characteristic fungal elements and Splendore–Hoeppli phenomenon.
3. Peripheral eosinophilia is appropriately discussed as an important diagnostic clue, but the eosinophil count for this patient is not reported. If available, adding the absolute or relative eosinophil count would improve the clinical description.
4. As the manuscript is presented as a “Case Report and Literature Review” and includes approximate case counts and clinical frequencies, a brief description of how the literature was identified would be useful. A concise description of the narrative search would be sufficient.
5. The temporal association with the postpartum period is noteworthy and adds interest to the case. Since this remains a hypothesis, the authors may wish to slightly temper the wording in the Abstract, Discussion, and Conclusions so that puerperium is presented as a possible association rather than an established predisposing factor.
6. It would be helpful to clarify the terminology used to describe the extent of disease. In particular, the terms “disseminated” and “biliary tree involvement” may merit more precise wording if hematogenous dissemination or direct bile-duct involvement was not definitively demonstrated.
7. Figure 8 is a useful practical summary. The authors may wish to indicate more clearly that the proposed diagnostic and management pathway represents a pragmatic approach based on the available literature and this case rather than a validated guideline. Similarly, the treatment statements in Table 4, particularly those concerning amphotericin B resistance, could be phrased cautiously given the limited evidence available for this rare infection.

Overall, this is a clinically valuable case and the manuscript is well presented. The points above are mainly intended to clarify the diagnostic evidence and to ensure that some of the broader interpretations remain appropriately cautious.

Author Response

We thank the reviewer for the careful and constructive assessment of our manuscript. We have addressed each point below; all corresponding revisions in the manuscript are highlighted in yellow.

Comment 1: Please provide some additional detail on how Basidiobolus ranarum was identified at the species level. It would be useful to indicate whether identification was based on conventional microscopic morphology alone or whether molecular or other confirmatory methods were also used.

Response 1: Thank you for pointing this out. We agree that the basis of the species-level identification should be stated explicitly. Identification was made by our clinical microbiology laboratory on conventional phenotypic grounds: growth on Sabouraud dextrose agar of waxy, glabrous, radially folded, buff-coloured colonies that acquired a greyish-brown surface on subculture, in conjunction with the histopathological demonstration of broad, pauci-septate hyphae surrounded by the Splendore–Hoeppli phenomenon in the gallbladder specimen. Molecular confirmation (panfungal PCR with sequencing) was unfortunately not available at our centre and could not be performed; we now state this explicitly as a limitation. In line with this, we have also softened the identification wording in the Abstract ("culture yielded an isolate phenotypically identified as B. ranarum") and in Section 3.4 ("Culture supports mycological identification…", with molecular methods presented as the definitive confirmatory step). The main change can be found in Section 2.4 (Diagnosis): "Species-level identification was made by the clinical microbiology laboratory on the basis of these characteristic colonial and growth features, taken together with the histopathological demonstration of broad, pauci-septate hyphae with the Splendore–Hoeppli phenomenon; molecular confirmation (panfungal PCR with sequencing) was not available at our centre and could not be performed."

Comment 2: The histopathological findings are central to the diagnosis. If an appropriate image is available, the authors may wish to consider including a representative histopathology figure showing the characteristic fungal elements and Splendore–Hoeppli phenomenon.

Response 2: We fully agree that a representative photomicrograph would strengthen the report, and we made every effort to obtain one. Regrettably, the cholecystectomy and the initial histopathological processing were performed at an external facility, and the stained sections could not be retrieved for photography despite our requests. We have added a sentence to Section 2.4 to state this transparently, so that readers understand why a histopathology figure is not shown: "Because the cholecystectomy and initial histopathological processing were performed at an external facility, photomicrographs of the stained sections were unfortunately not retrievable for publication." The detailed morphological description of the findings is retained in the text.

Comment 3: Peripheral eosinophilia is appropriately discussed as an important diagnostic clue, but the eosinophil count for this patient is not reported. If available, adding the absolute or relative eosinophil count would improve the clinical description.

Response 3: Thank you for this helpful observation. We have retrieved the patient's differential white-cell count from the initial admission and now report it in Section 2.2 and as a new row in Table 1. The absolute eosinophil count was 2.62 × 10³/µL (21.7% of leukocytes), representing marked peripheral eosinophilia, and the peripheral blood smear confirmed moderate eosinophilia without eosinophil atypia. We agree this materially strengthens the clinical description, as peripheral eosinophilia is among the key diagnostic clues to basidiobolomycosis. The added text in Section 2.2 reads: "The differential white-cell count performed during the initial admission showed marked peripheral eosinophilia, with an absolute eosinophil count of 2.62 × 10³/µL (21.7% of leukocytes), and the peripheral blood smear confirmed moderate eosinophilia without eosinophil atypia—a finding of particular interest given the recognised association of basidiobolomycosis with peripheral eosinophilia."

Comment 4: As the manuscript is presented as a "Case Report and Literature Review" and includes approximate case counts and clinical frequencies, a brief description of how the literature was identified would be useful. A concise description of the narrative search would be sufficient.

Response 4: We agree. A concise description of the narrative search strategy has been added at the beginning of the Discussion (Section 3, first paragraph): "For the accompanying narrative literature review, we searched PubMed/MEDLINE and Google Scholar from inception to June 2026 using combinations of the terms 'basidiobolomycosis', 'Basidiobolus ranarum', 'gastrointestinal', 'hepatobiliary' and 'biliary', limited to English-language publications, and hand-searched the reference lists of retrieved articles for additional cases. This was a narrative rather than a systematic review; accordingly, the case counts and clinical frequencies cited below are approximate, are drawn from the referenced series and reviews, and may overlap between sources."

Comment 5: The temporal association with the postpartum period is noteworthy and adds interest to the case. Since this remains a hypothesis, the authors may wish to slightly temper the wording in the Abstract, Discussion, and Conclusions so that puerperium is presented as a possible association rather than an established predisposing factor.

Response 5: We agree entirely and have tempered the wording in all three locations so that the puerperium is consistently framed as a possible, unproven association. The Abstract now ends: "We hypothesise that the early puerperium could represent a possible, though as yet unproven, window of susceptibility to this infection." Section 3.2 now reads "…the temporal association in our case—symptoms beginning some two months postpartum—is noteworthy, although it may be coincidental." Section 3.6 now describes the association as an unproven, possibly coincidental hypothesis, and the Conclusions now state: "…the puerperium may possibly represent a window of susceptibility to this infection, although this remains a hypothesis…"

Comment 6: It would be helpful to clarify the terminology used to describe the extent of disease. In particular, the terms "disseminated" and "biliary tree involvement" may merit more precise wording if hematogenous dissemination or direct bile-duct involvement was not definitively demonstrated.

Response 6: Thank you for this important point. Haematogenous dissemination was indeed not microbiologically proven, and direct bile-duct (intraductal) invasion was not demonstrated. We have therefore (i) replaced "disseminated" with "multifocal" when describing our patient throughout the Introduction, Section 2.4 and the Conclusions; (ii) used "biliary tract involvement" consistently; and (iii) added an explicit definition in Section 2.4: "Throughout this report, 'biliary tract involvement' denotes histologically confirmed infection of the gallbladder with contiguous inflammatory extension along the gallbladder bed and porta hepatis, rather than demonstrated invasion of the bile ducts, and the multifocal distribution most plausibly reflects contiguous or intramural spread, as haematogenous dissemination was not microbiologically proven." Section 3.3 has been aligned with this wording.

Comment 7: Figure 8 is a useful practical summary. The authors may wish to indicate more clearly that the proposed diagnostic and management pathway represents a pragmatic approach based on the available literature and this case rather than a validated guideline. Similarly, the treatment statements in Table 4, particularly those concerning amphotericin B resistance, could be phrased cautiously given the limited evidence available for this rare infection.

Response 7: We agree on both counts. The legend of Figure 8 now explicitly states: "This pathway is a pragmatic synthesis of the available literature and the present case; it has not been prospectively validated and is not intended as a formal guideline." In Table 4, the amphotericin B entry has been rephrased from ">50% resistance" to "Variable; failures reported", with the note "In vitro resistance and clinical failures reported in limited case data; interpret cautiously", and a corresponding cautionary sentence has been added to Section 3.5.

We are grateful for the reviewer's thoughtful comments, which have improved the precision and balance of the manuscript.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This is a very well-studied and comprehensive case. Suggestions:
- Italicize the names of the fungi.
- Since biopsies and cultures were performed, it would be highly appropriate to include images of both; this enriches the work and provides the reader with precise information.
- In the discussion, mention that potassium iodide also serves as a treatment and include a reference.

Author Response

We thank the reviewer for the positive assessment of our manuscript. We have addressed each point below; all corresponding revisions in the manuscript are highlighted in yellow.

Comment 1: Italicize the names of the fungi.

Response 1: Thank you — done. All genus and species names of microorganisms (Basidiobolus ranarum, B. ranarum, Basidiobolus, Clostridioides difficile, C. difficile, Helicobacter pylori, H. pylori) are now italicised consistently throughout the manuscript, including the Abstract, Keywords, tables, figure legends and reference list; higher-rank taxa such as the order Entomophthorales are correctly set in roman (non-italic) type.

Comment 2: Since biopsies and cultures were performed, it would be highly appropriate to include images of both; this enriches the work and provides the reader with precise information.

Response 2: We agree that such images enrich a mycological case report. Culture images are already included as Figure 7, which shows (A) the waxy, glabrous, radially folded buff colony on Sabouraud dextrose agar and (B) the greyish-brown surface that developed on subculture on blood agar. Regarding the histopathology, we made every effort to obtain a photomicrograph, but the cholecystectomy and the initial histopathological processing were performed at an external facility and the stained sections could not be retrieved for photography. We have added a sentence to Section 2.4 stating this transparently: "Because the cholecystectomy and initial histopathological processing were performed at an external facility, photomicrographs of the stained sections were unfortunately not retrievable for publication."

Comment 3: In the discussion, mention that potassium iodide also serves as a treatment and include a reference.

Response 3: Thank you for this valuable suggestion. We have added potassium iodide to the Discussion (Section 3.5) and to Table 4, together with a supporting reference (new reference 26: Sanaei Dashti A, et al. Gastro-intestinal basidiobolomycosis in a 2-year-old boy: dramatic response to potassium iodide. Paediatr Int Child Health 2018;38:150–153). The added text reads: "Saturated potassium iodide solution, long used for subcutaneous basidiobolomycosis, is a further inexpensive and readily available option: it has produced complete resolution of gastrointestinal disease refractory to amphotericin B and itraconazole in at least one paediatric case, and it features in several of the combination regimens reported in recent series [24,26]."

We thank the reviewer for suggestions that have enriched the therapeutic discussion.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript is well-presented, interesting, and appears to be quite comprehensive for the case presented. Overall, it will be a valuable contribution to resolving similar cases by ruling out pathologies that act in a similar manner. Just as minor comments, could the authors consider better demonstrating that the fungal specimen corresponds exactly to that species of fungus? How exactly did the authors arrive at the genus-species identification of the fungus? There are no morphological preparations of the fungus, histological sections with fungal staining, or molecular identification. The authors should consider adding this last criterion to provide greater support for their findings, not just relying on the macroscopic growth of the fungus. Finally, all names of bacterial and fungal microorganisms should be correctly written in italics.

Author Response

We thank the reviewer for the positive evaluation of our manuscript. We have addressed each point below; all corresponding revisions in the manuscript are highlighted in yellow.

Comment 1: Could the authors consider better demonstrating that the fungal specimen corresponds exactly to that species of fungus? How exactly did the authors arrive at the genus-species identification of the fungus? There are no morphological preparations of the fungus, histological sections with fungal staining, or molecular identification. The authors should consider adding this last criterion to provide greater support for their findings, not just relying on the macroscopic growth of the fungus.

Response 1: Thank you for raising this important point, which was also raised by Reviewer 1. We have now stated explicitly in Section 2.4 how the species-level identification was reached. The diagnosis did not rest on macroscopic colony growth alone: it was based on the combination of (i) histopathology of the gallbladder specimen with fungal stains, showing broad, thin-walled, pauci-septate hyphae cuffed by the intensely eosinophilic Splendore–Hoeppli phenomenon within a dense eosinophilic and granulomatous infiltrate — an appearance regarded as highly characteristic of basidiobolomycosis; (ii) culture of the drained pus on Sabouraud dextrose agar yielding waxy, glabrous, radially folded buff colonies that acquired a greyish-brown surface on subculture, phenotypic features consistent with Basidiobolus ranarum; and (iii) a compatible clinical and radiological picture in an endemic region. We agree, however, that molecular identification would provide the strongest support. Panfungal PCR with sequencing was unfortunately not available at our centre and could not be performed, and the isolate is no longer retrievable for retrospective sequencing. We now acknowledge this explicitly as a limitation in Section 2.4: "Species-level identification was made by the clinical microbiology laboratory on the basis of these characteristic colonial and growth features, taken together with the histopathological demonstration of broad, pauci-septate hyphae with the Splendore–Hoeppli phenomenon; molecular confirmation (panfungal PCR with sequencing) was not available at our centre and could not be performed." In addition, we have softened the identification wording elsewhere: the Abstract now states that "culture yielded an isolate phenotypically identified as B. ranarum", and Section 3.4 now reads "Culture supports mycological identification…", with molecular methods presented as the step that can provide definitive species-level confirmation.

Comment 2: Finally, all names of bacterial and fungal microorganisms should be correctly written in italics.

Response 2: Thank you — done. All genus and species names of microorganisms (Basidiobolus ranarum, B. ranarum, Basidiobolus, Clostridioides difficile, C. difficile, Helicobacter pylori, H. pylori) are now italicised consistently throughout the manuscript, including the Abstract, Keywords, tables, figure legends and reference list; higher-rank taxa such as the order Entomophthorales are correctly set in roman (non-italic) type.

We are grateful for the reviewer's emphasis on rigorous mycological identification, which we have addressed as fully as our records allow.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for the careful revision of the manuscript. The authors have addressed the substantive concerns raised during the previous review and have improved the precision and balance of the report.

In particular, the revised manuscript now appropriately qualifies the possible association with the postpartum period, more clearly defines the extent and nature of the biliary involvement, avoids implying haematogenous dissemination where this was not demonstrated, and provides a more transparent description of the microbiological identification and its limitations. The addition of the peripheral eosinophil count, clarification of the narrative literature review methodology, and more cautious interpretation of the available therapeutic evidence further strengthen the manuscript.

I have no additional substantive comments. In my view, the manuscript is now suitable for publication in its present form.

Author Response

We thank the reviewer for carefully reassessing our manuscript and for the positive evaluation of the revisions. Your constructive feedback has helped us clarify the clinical findings, acknowledge the diagnostic limitations, and present a more balanced interpretation of the case and available evidence. We are pleased that the revisions have addressed your concerns, and we appreciate your time and contribution to improving the manuscript.