Primary colonic malignant peripheral nerve sheath tumor with biphasic morphology: A case report

Table 1 Laboratory test results

Test Item	Result	Flag	Reference range	Unit
WBC	9.86	↑	3.50-9.50	× 109/L
NEUT%	82.8	↑	40.0-75.0	%
HGB	61	↓	130-175	g/L
CEA	1.58		< 5.00	ng/mL
CA-125	76.20	↑	< 24.00	U/mL

WBC: White blood cell count; NEUT%: Neutrophil percentage; HGB: Hemoglobin; CEA: Carcinoembryonic antigen; CA-125: Carbohydrate antigen 125.

Table 2 Clinical features, treatment, and follow-up outcomes of reported cases of colonic malignant peripheral nerve sheath tumor

Ref.	Age/sex	NF1 history	Presenting symptoms	Tumor location	Tumor size (cm)	Surgical procedure	Margin status	Adjuvant therapy	Follow-up outcome
Present case	75/M	No	Abdominal pain, abdominal distension	Ascending colon	17 × 13 × 3	Right hemicolectomy	Negative	None	Died on postoperative day 13
Rawal et al[4]	25/M	No	Abdominal distension	Transverse colon	20 × 18 × 10	Transverse colectomy	Negative	None	No recurrence during 6 months of follow-up
Cyriac et al[5]	13/M	No	Abdominal pain	Transverse colon	7 × 3.5	Transverse colectomy	Negative	None	No recurrence during 6 months of follow-up
Lee et al[6]	Neonate, 2 days/F	No	Abdominal distension, vomiting	Ascending colon	5 × 2.5 × 2.5	Partial colectomy	Negative	None	No recurrence during 6 months of follow-up
Marwah et al[7]	30/F	Yes	Abdominal pain	Splenic flexure	10 × 10 × 6	Segmental colectomy	Negative	None	Died 18 months after surgery because of recurrent disease
Al-Shehari et al[8]	46/F	No	Abdominal pain	Sigmoid colon	6 × 5.3 × 5.2	Sigmoid colectomy	Negative	None	No recurrence during 6 months of follow-up
Lakkasani et al[9]	71/M	No	Abdominal pain, anorexia	Right colon and small bowel	Colon: 10; small bowel: 8	Palliative resection	NA	None	Multiple metastases detected 6 months after surgery

NF1: Neurofibromatosis type 1; M: Male; F: Female.

Table 3 Histologic features and immunohistochemical findings of reported colonic malignant peripheral nerve sheath tumor

Ref.	Histologic features	Immunohistochemical findings
Present case	The tumor showed a biphasic morphology composed of spindle cells arranged in fascicles and small round cells distributed diffusely, set in a vascular-rich stroma with extensive myxoid change	S-100 (+); AE1/AE3 (-); SMA (-); Desmin (-); GFAP (-); NKX2.2 (-); FLI1 (-); SOX10 (-); CD117 (-); CD34 positive only in vascular structures; complete loss of H3K27me3; Ki-67 approximately 90%
Rawal et al[4]	Predominantly composed of spindle cell fascicles	S-100 (+); CD117 (-); DOG1 (-); CD34 (-)
Cyriac et al[5]	Composed of spindle cells and epithelioid cells	S-100 (+); Vimentin (+); HMB45 (-); CD117 (-); DOG1 (-)
Lee et al[6]	Predominantly composed of spindle cell fascicles	S-100 (+); Vimentin (+); AE1/AE3 (-); Desmin (-); Myosin (-); Ki-67 5%-10%
Marwah et al[7]	Predominantly composed of spindle cell fascicles	S-100 (+); CD117 (-); NSE (-); Ki-67 approximately 20%
Al-Shehari et al[8]	Predominantly composed of spindle cell fascicles	S-100 (+); SOX10 (+); CD117 (-); CD34 (-); DOG1 (-); SMA (-); Ki-67 10%
Lakkasani et al[9]	Composed of spindle cell fascicles and pleomorphic cells, with focal rhabdomyoblastic differentiation	S-100 (+); Ki-67 approximately 70%

Table 4 Major differential diagnoses considered in the present case and the corresponding pathologic basis

Tumor type	Key morphologic features	Common immunophenotype	Findings in the present case	Diagnostic interpretation
MPNST	Predominantly composed of spindle cells, often with marked atypia, high mitotic activity, and focal necrosis; some cases may show heterologous differentiation or marked morphologic heterogeneity	S-100 often focal or patchy positive; SOX10 may be positive or negative; complete loss of H3K27me3 is common in high-grade tumors	Coexistence of spindle cells and small round cells; S-100 positive, SOX10 negative; complete loss of H3K27me3; Ki-67 approximately 90%	Supported
Gastrointestinal stromal tumor	Spindle cell or epithelioid morphology, often arranged in fascicular, whorled, or palisading patterns	CD117 positive, DOG1 positive, often with CD34 positivity	CD117 negative; DOG1 negative	Excluded
Leiomyosarcoma	Fascicular spindle cell proliferation with eosinophilic cytoplasm and cigar-shaped nuclei	SMA positive, Desmin positive, h-caldesmon positive	SMA negative; dsmin negative	Excluded
Ewing sarcoma/primitive neuroectodermal tumor	Relatively uniform small round blue cells with scant cytoplasm, sometimes with necrosis	FLI1 positive, NKX2.2 positive, EWSR1 rearrangement	NKX2.2 negative; FLI1 negative; and a definite spindle cell component was present	Excluded
Clear cell sarcoma	Clear or eosinophilic tumor cells arranged in nests or fascicles	S-100 positive, HMB45 positive, Melan-A positive	HMB45 negative	Excluded
Melanoma	May show spindle cell or epithelioid morphology with marked atypia, sometimes with melanin pigment	S-100 positive, SOX10 positive, HMB45 positive, Melan-A positive	HMB45 negative; SOX10 negative; no history of melanoma	Excluded
Synovial sarcoma	Monophasic tumors are often composed of relatively uniform spindle cells and may show a vascular-rich background	AE1/AE3 positive, EMA positive, TLE1 positive	AE1/AE3 negative; EMA negative	Excluded

MPNST: Malignant peripheral nerve sheath tumor.

Table 5 Postoperative complete blood count findings

Test item	Result	Flag	Reference range	Unit
WBC	4.75		3.50-9.50	× 109/L
NEUT%	87.6	↑	40.0-75.0	%
LYMPH%	10.5	↓	20.0-50.0	%
HGB	73	↓	130-175	g/L
PLT	62	↓	125-350	× 109/L

WBC: White blood cell count; NEUT%: Neutrophil percentage; LYMPH%: Lymphocyte percentage; HGB: Hemoglobin; PLT: Platelet count.

Table 6 Biochemical analysis of peritoneal fluid

Test item	Result	Flag	Reference range	Unit
TP	3.3		< 25.0	g/L
LDH	1021.75	↑	< 200	U/L
GLU	4.6		3.6-5.5	mmol/L
ADA	7.0		< 40.0	U/L

TP: Total protein; LDH: Lactate dehydrogenase; GLU: Glucose; ADA: Adenosine deaminase.